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Liu Q, Jiang K, Duan S, Zhao N, Shen Y, Zhu L, Zhang KQ, Yang J. Identification of a transcription factor AoMsn2 of the Hog1 signaling pathway contributes to fungal growth, development and pathogenicity in Arthrobotrys oligospora. J Adv Res 2025; 68:1-15. [PMID: 38331317 PMCID: PMC11785577 DOI: 10.1016/j.jare.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/20/2024] [Accepted: 02/03/2024] [Indexed: 02/10/2024] Open
Abstract
INTRODUCTION Arthrobotrys oligospora has been utilized as a model strain to study the interaction between fungi and nematodes owing to its ability to capture nematodes by developing specialized traps. A previous study showed that high-osmolarity glycerol (Hog1) signaling regulates the osmoregulation and nematocidal activity of A. oligospora. However, the function of downstream transcription factors of the Hog1 signaling in the nematode-trapping (NT) fungi remains unclear. OBJECTIVE This study aimed to investigate the functions and potential regulatory network of AoMsn2, a downstream transcription factor of the Hog1 signaling pathway in A. oligospora. METHODS The function of AoMsn2 was characterized using targeted gene deletion, phenotypic experiments, real-time quantitative PCR, RNA sequencing, untargeted metabolomics, and yeast two-hybrid analysis. RESULTS Loss of Aomsn2 significantly enlarged and swollen the hyphae, with an increase in septa and a significant decrease in nuclei. In particular, spore yield, spore germination rate, traps, and nematode predation efficiency were remarkably decreased in the mutants. Phenotypic and transcriptomic analyses revealed that AoMsn2 is essential for fatty acid metabolism and autophagic pathways. Additionally, untargeted metabolomic analysis identified an important function of AoMsn2 in the modulation of secondary metabolites. Furtherly, we analyzed the protein interaction network of AoMsn2 based on the Kyoto Encyclopedia of Genes and Genomes pathway map and the online website STRING. Finally, Hog1 and six putative targeted proteins of AoMsn2 were identified by Y2H analysis. CONCLUSION Our study reveals that AoMsn2 plays crucial roles in the growth, conidiation, trap development, fatty acid metabolism, and secondary metabolism, as well as establishes a broad basis for understanding the regulatory mechanisms of trap morphogenesis and environmental adaptation in NT fungi.
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Affiliation(s)
- Qianqian Liu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, and School of Life Science, Yunnan University, Kunming 650032, China
| | - Kexin Jiang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, and School of Life Science, Yunnan University, Kunming 650032, China
| | - Shipeng Duan
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, and School of Life Science, Yunnan University, Kunming 650032, China
| | - Na Zhao
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, and School of Life Science, Yunnan University, Kunming 650032, China
| | - Yanmei Shen
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, and School of Life Science, Yunnan University, Kunming 650032, China
| | - Lirong Zhu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, and School of Life Science, Yunnan University, Kunming 650032, China
| | - Ke-Qin Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, and School of Life Science, Yunnan University, Kunming 650032, China
| | - Jinkui Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, and School of Life Science, Yunnan University, Kunming 650032, China.
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Filali-Mouncef Y, Leytens A, Vargas Duarte P, Zampieri M, Dengjel J, Reggiori F. An APEX2-based proximity-dependent biotinylation assay with temporal specificity to study protein interactions during autophagy in the yeast Saccharomyces cerevisiae. Autophagy 2024; 20:2323-2337. [PMID: 38958087 PMCID: PMC11423678 DOI: 10.1080/15548627.2024.2366749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 05/30/2024] [Accepted: 06/07/2024] [Indexed: 07/04/2024] Open
Abstract
Autophagosome biogenesis is a complex process orchestrated by dynamic interactions between Atg (autophagy-related) proteins and characterized by the turnover of specific cargoes, which can differ over time and depending on how autophagy is stimulated. Proteomic analyses are central to uncover protein-protein interaction networks and when combined with proximity-dependent biotinylation or proximity labeling (PL) approaches, they also permit to detect transient and weak interactions. However, current PL procedures for yeast Saccharomyces cerevisiae, one of the leading models for the study of autophagy, do not allow to keep temporal specificity and thus identify interactions and cargoes at a precise time point upon autophagy induction. Here, we present a new ascorbate peroxidase 2 (APEX2)-based PL protocol adapted to yeast that preserves temporal specificity and allows uncovering neighbor proteins by either western blot or proteomics. As a proof of concept, we applied this new method to identify Atg8 and Atg9 interactors and detected known binding partners as well as potential uncharacterized ones in rich and nitrogen starvation conditions. Also, as a proof of concept, we confirmed the spatial proximity interaction between Atg8 and Faa1. We believe that this protocol will be a new important experimental tool for all those researchers studying the mechanism and roles of autophagy in yeast, but also other cellular pathways in this model organism.Abbreviations: APEX2, ascorbate peroxidase 2, Atg, autophagy-related; BP, biotin phenol; Cvt, cytoplasm-to-vacuole targeting; ER, endoplasmic reticulum; LN2, liquid nitrogen; MS, mass spectrometry; PAS, phagophore assembly site; PL, proximity labeling; PE, phosphatidylethanolamine; PPINs, protein-protein interaction networks; PPIs, protein-protein interactions; RT, room temperature; SARs, selective autophagy receptors; WT, wild-type.
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Affiliation(s)
- Yasmina Filali-Mouncef
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, AV, The Netherlands
| | - Alexandre Leytens
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | | | - Mattia Zampieri
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Jörn Dengjel
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, AV, The Netherlands
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus C, Denmark
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Velle KB, Swafford AJM, Garner E, Fritz-Laylin LK. Actin network evolution as a key driver of eukaryotic diversification. J Cell Sci 2024; 137:jcs261660. [PMID: 39120594 PMCID: PMC12050087 DOI: 10.1242/jcs.261660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2024] Open
Abstract
Eukaryotic cells have been evolving for billions of years, giving rise to wildly diverse cell forms and functions. Despite their variability, all eukaryotic cells share key hallmarks, including membrane-bound organelles, heavily regulated cytoskeletal networks and complex signaling cascades. Because the actin cytoskeleton interfaces with each of these features, understanding how it evolved and diversified across eukaryotic phyla is essential to understanding the evolution and diversification of eukaryotic cells themselves. Here, we discuss what we know about the origin and diversity of actin networks in terms of their compositions, structures and regulation, and how actin evolution contributes to the diversity of eukaryotic form and function.
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Affiliation(s)
- Katrina B. Velle
- Department of Biology, University of Massachusetts Dartmouth, Dartmouth, MA 02747, USA
| | | | - Ethan Garner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
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4
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Liu D, Yuan H, Chen S, Ferro-Novick S, Novick P. Different ER-plasma membrane tethers play opposing roles in autophagy of the cortical ER. Proc Natl Acad Sci U S A 2024; 121:e2321991121. [PMID: 38838012 PMCID: PMC11181077 DOI: 10.1073/pnas.2321991121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 05/08/2024] [Indexed: 06/07/2024] Open
Abstract
The endoplasmic reticulum (ER) undergoes degradation by selective macroautophagy (ER-phagy) in response to starvation or the accumulation of misfolded proteins within its lumen. In yeast, actin assembly at sites of contact between the cortical ER (cER) and endocytic pits acts to displace elements of the ER from their association with the plasma membrane (PM) so they can interact with the autophagosome assembly machinery near the vacuole. A collection of proteins tether the cER to the PM. Of these, Scs2/22 and Ist2 are required for cER-phagy, most likely through their roles in lipid transport, while deletion of the tricalbins, TCB1/2/3, bypasses those requirements. An artificial ER-PM tether blocks cER-phagy in both the wild type (WT) and a strain lacking endogenous tethers, supporting the importance of cER displacement from the PM. Scs2 and Ist2 can be cross-linked to the selective cER-phagy receptor, Atg40. The COPII cargo adaptor subunit, Lst1, associates with Atg40 and is required for cER-phagy. This requirement is also bypassed by deletion of the ER-PM tethers, suggesting a role for Lst1 prior to the displacement of the cER from the PM during cER-phagy. Although pexophagy and mitophagy also require actin assembly, deletion of ER-PM tethers does not bypass those requirements. We propose that within the context of rapamycin-induced cER-phagy, Scs2/22, Ist2, and Lst1 promote the local displacement of an element of the cER from the cortex, while Tcb1/2/3 act in opposition, anchoring the cER to the plasma membrane.
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Affiliation(s)
- Dongmei Liu
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA92093-0668
| | - Hua Yuan
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA92093-0668
| | - Shuliang Chen
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA92093-0668
| | - Susan Ferro-Novick
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA92093-0668
| | - Peter Novick
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA92093-0668
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Theodore CJ, Wagner LH, Campellone KG. Autophagosome turnover requires Arp2/3 complex-mediated maintenance of lysosomal integrity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.12.584718. [PMID: 38559247 PMCID: PMC10980047 DOI: 10.1101/2024.03.12.584718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Autophagy is an intracellular degradation process that maintains homeostasis, responds to stress, and plays key roles in the prevention of aging and disease. Autophagosome biogenesis, vesicle rocketing, and autolysosome tubulation are controlled by multiple actin nucleation factors, but the impact of actin assembly on completion of the autophagic pathway is not well understood. Here we studied autophagosome and lysosome remodeling in fibroblasts harboring an inducible knockout (iKO) of the Arp2/3 complex, an essential actin nucleator. Arp2/3 complex ablation resulted in increased basal levels of autophagy receptors and lipidated membrane proteins from the LC3 and GABARAP families. Under both steady-state and starvation conditions, Arp2/3 iKO cells accumulated abnormally high numbers of autolysosomes, suggesting a defect in autophagic flux. The inability of Arp2/3 complex-deficient cells to complete autolysosome degradation and turnover is explained by the presence of damaged, leaky lysosomes. In cells treated with an acute lysosomal membrane-damaging agent, the Arp2/3-activating protein WHAMM is recruited to lysosomes, where Arp2/3 complex-dependent actin assembly is crucial for restoring intact lysosomal structure. These results establish the Arp2/3 complex as a central player late in the canonical autophagy pathway and reveal a new role for the actin nucleation machinery in maintaining lysosomal integrity.
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Affiliation(s)
- Corey J. Theodore
- Department of Molecular and Cell Biology; University of Connecticut, Storrs CT, USA
- Institute for Systems Genomics; University of Connecticut, Storrs CT, USA
| | - Lianna H. Wagner
- Department of Molecular and Cell Biology; University of Connecticut, Storrs CT, USA
- Institute for Systems Genomics; University of Connecticut, Storrs CT, USA
| | - Kenneth G. Campellone
- Department of Molecular and Cell Biology; University of Connecticut, Storrs CT, USA
- Institute for Systems Genomics; University of Connecticut, Storrs CT, USA
- Center on Aging, UConn Health; University of Connecticut, Storrs CT, USA
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Dong Y, Quan C. NPFs-mediated actin cytoskeleton: a new viewpoint on autophagy regulation. Cell Commun Signal 2024; 22:111. [PMID: 38347641 PMCID: PMC10860245 DOI: 10.1186/s12964-023-01444-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/18/2023] [Indexed: 02/15/2024] Open
Abstract
Macroautophagy/autophagy is a lysosome-dependent catabolic process induced by various cellular stress conditions, maintaining the homeostasis of cells, tissues and organs. Autophagy is a series of membrane-related events involving multiple autophagy-related (ATG) proteins. Most studies to date have focused on various signaling pathways affecting ATG proteins to control autophagy. However, mounting evidence reveals that the actin cytoskeleton acts on autophagy-associated membranes to regulate different events of autophagy. The actin cytoskeleton assists in vesicle formation and provides the mechanical forces for cellular activities that involve membrane deformation. Although the interaction between the actin cytoskeleton and membrane makes the role of actin in autophagy recognized, how the actin cytoskeleton is recruited and assembles on membranes during autophagy needs to be detailed. Nucleation-promoting factors (NPFs) activate the Arp2/3 complex to produce actin cytoskeleton. In this review, we summarize the important roles of the actin cytoskeleton in autophagy regulation and focus on the effect of NPFs on actin cytoskeleton assembly during autophagy, providing new insights into the occurrence and regulatory mechanisms of autophagy. Video Abstract.
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Affiliation(s)
- Yuan Dong
- The Key Laboratory of Pathobiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, 126 Xinmin Avenue, ChangchunJilin, 130021, China
| | - Chengshi Quan
- The Key Laboratory of Pathobiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, 126 Xinmin Avenue, ChangchunJilin, 130021, China.
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7
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Nambiar A, Manjithaya R. Driving autophagy - the role of molecular motors. J Cell Sci 2024; 137:jcs260481. [PMID: 38329417 DOI: 10.1242/jcs.260481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024] Open
Abstract
Most of the vesicular transport pathways inside the cell are facilitated by molecular motors that move along cytoskeletal networks. Autophagy is a well-explored catabolic pathway that is initiated by the formation of an isolation membrane known as the phagophore, which expands to form a double-membraned structure that captures its cargo and eventually moves towards the lysosomes for fusion. Molecular motors and cytoskeletal elements have been suggested to participate at different stages of the process as the autophagic vesicles move along cytoskeletal tracks. Dynein and kinesins govern autophagosome trafficking on microtubules through the sequential recruitment of their effector proteins, post-translational modifications and interactions with LC3-interacting regions (LIRs). In contrast, myosins are actin-based motors that participate in various stages of the autophagic flux, as well as in selective autophagy pathways. However, several outstanding questions remain with regard to how the dominance of a particular motor protein over another is controlled, and to the molecular mechanisms that underlie specific disease variants in motor proteins. In this Review, we aim to provide an overview of the role of molecular motors in autophagic flux, as well as highlight their dysregulation in diseases, such as neurodegenerative disorders and pathogenic infections, and ageing.
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Affiliation(s)
- Akshaya Nambiar
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Ravi Manjithaya
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
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8
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Lee SY, Choi SH, Kim Y, Ahn HS, Ko YG, Kim K, Chi SW, Kim H. Migrasomal autophagosomes relieve endoplasmic reticulum stress in glioblastoma cells. BMC Biol 2024; 22:23. [PMID: 38287397 PMCID: PMC10826056 DOI: 10.1186/s12915-024-01829-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 01/16/2024] [Indexed: 01/31/2024] Open
Abstract
BACKGROUND Glioblastoma (GBM) is more difficult to treat than other intractable adult tumors. The main reason that GBM is so difficult to treat is that it is highly infiltrative. Migrasomes are newly discovered membrane structures observed in migrating cells. Thus, they can be generated from GBM cells that have the ability to migrate along the brain parenchyma. However, the function of migrasomes has not yet been elucidated in GBM cells. RESULTS Here, we describe the composition and function of migrasomes generated along with GBM cell migration. Proteomic analysis revealed that LC3B-positive autophagosomes were abundant in the migrasomes of GBM cells. An increased number of migrasomes was observed following treatment with chloroquine (CQ) or inhibition of the expression of STX17 and SNAP29, which are involved in autophagosome/lysosome fusion. Furthermore, depletion of ITGA5 or TSPAN4 did not relieve endoplasmic reticulum (ER) stress in cells, resulting in cell death. CONCLUSIONS Taken together, our study suggests that increasing the number of autophagosomes, through inhibition of autophagosome/lysosome fusion, generates migrasomes that have the capacity to alleviate cellular stress.
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Affiliation(s)
- Seon Yong Lee
- Department of Biotechnology, Korea University, Seoul, Republic of Korea
- Institute of Animal Molecular Biotechnology, Korea University, Seoul, Republic of Korea
| | - Sang-Hun Choi
- Department of Biotechnology, Korea University, Seoul, Republic of Korea
- Institute of Animal Molecular Biotechnology, Korea University, Seoul, Republic of Korea
| | - Yoonji Kim
- Department of Biotechnology, Korea University, Seoul, Republic of Korea
| | - Hee-Sung Ahn
- Convergence Medicine Research Center, Asan Institute for Life Sciences, Asan Medical Center, Seoul, Republic of Korea
| | - Young-Gyu Ko
- Department of Life Sciences, Korea University, Seoul, Republic of Korea
| | - Kyunggon Kim
- Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sung Wook Chi
- Department of Life Sciences, Korea University, Seoul, Republic of Korea
- Division of Life Sciences, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
| | - Hyunggee Kim
- Department of Biotechnology, Korea University, Seoul, Republic of Korea.
- Institute of Animal Molecular Biotechnology, Korea University, Seoul, Republic of Korea.
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Martinek J, Cifrová P, Vosolsobě S, García-González J, Malínská K, Mauerová Z, Jelínková B, Krtková J, Sikorová L, Leaves I, Sparkes I, Schwarzerová K. ARP2/3 complex associates with peroxisomes to participate in pexophagy in plants. NATURE PLANTS 2023; 9:1874-1889. [PMID: 37845336 DOI: 10.1038/s41477-023-01542-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 09/11/2023] [Indexed: 10/18/2023]
Abstract
Actin-related protein (ARP2/3) complex is a heteroheptameric protein complex, evolutionary conserved in all eukaryotic organisms. Its conserved role is based on the induction of actin polymerization at the interface between membranes and the cytoplasm. Plant ARP2/3 has been reported to participate in actin reorganization at the plasma membrane during polarized growth of trichomes and at the plasma membrane-endoplasmic reticulum contact sites. Here we demonstrate that individual plant subunits of ARP2/3 fused to fluorescent proteins form motile spot-like structures in the cytoplasm that are associated with peroxisomes in Arabidopsis and tobacco. ARP2/3 is found at the peroxisome periphery and contains the assembled ARP2/3 complex and the WAVE/SCAR complex subunit NAP1. This ARP2/3-positive peroxisomal domain colocalizes with the autophagosome and, under conditions that affect the autophagy, colocalization between ARP2/3 and the autophagosome increases. ARP2/3 subunits co-immunoprecipitate with ATG8f and peroxisome-associated ARP2/3 interact in vivo with the ATG8f marker. Since mutants lacking functional ARP2/3 complex have more peroxisomes than wild type, we suggest that ARP2/3 has a novel role in the process of peroxisome degradation by autophagy, called pexophagy.
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Affiliation(s)
- Jan Martinek
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Petra Cifrová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Stanislav Vosolsobě
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Judith García-González
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Kateřina Malínská
- Imaging Facility of Institute of Experimental Botany AS CR, Prague, Czech Republic
| | - Zdeňka Mauerová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Barbora Jelínková
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jana Krtková
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Lenka Sikorová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Ian Leaves
- Biosciences, CLES, Exeter University, Exeter, UK
| | - Imogen Sparkes
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Kateřina Schwarzerová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic.
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Yuan G, Gao H, Yang T. Exploring the Role of the Plant Actin Cytoskeleton: From Signaling to Cellular Functions. Int J Mol Sci 2023; 24:15480. [PMID: 37895158 PMCID: PMC10607326 DOI: 10.3390/ijms242015480] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/06/2023] [Accepted: 10/21/2023] [Indexed: 10/29/2023] Open
Abstract
The plant actin cytoskeleton is characterized by the basic properties of dynamic array, which plays a central role in numerous conserved processes that are required for diverse cellular functions. Here, we focus on how actins and actin-related proteins (ARPs), which represent two classical branches of a greatly diverse superfamily of ATPases, are involved in fundamental functions underlying signal regulation of plant growth and development. Moreover, we review the structure, assembly dynamics, and biological functions of filamentous actin (F-actin) from a molecular perspective. The various accessory proteins known as actin-binding proteins (ABPs) partner with F-actin to finely tune actin dynamics, often in response to various cell signaling pathways. Our understanding of the significance of the actin cytoskeleton in vital cellular activities has been furthered by comparison of conserved functions of actin filaments across different species combined with advanced microscopic techniques and experimental methods. We discuss the current model of the plant actin cytoskeleton, followed by examples of the signaling mechanisms under the supervision of F-actin related to cell morphogenesis, polar growth, and cytoplasmic streaming. Determination of the theoretical basis of how the cytoskeleton works is important in itself and is beneficial to future applications aimed at improving crop biomass and production efficiency.
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Affiliation(s)
| | | | - Tao Yang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China; (G.Y.); (H.G.)
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11
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Wang JM, Li ZF, Qi HY, Zhao Z, Yang WX. es-Arp3 and es-Eps8 regulate spermatogenesis via microfilaments in the seminiferous tubule of Eriocheir sinensis. Tissue Cell 2023; 81:102028. [PMID: 36709695 DOI: 10.1016/j.tice.2023.102028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/13/2022] [Accepted: 01/16/2023] [Indexed: 01/19/2023]
Abstract
Spermatogenesis is a complicated process that includes spermatogonia differentiation, spermatocytes meiosis, spermatids spermiogenesis and final release of spermatozoa. Actin-related protein 3 (Arp3) and epidermal growth factor receptor pathway substrate 8 (Eps8) are two actin binding proteins that regulate cell adhesion in seminiferous tubules during mammalian spermatogenesis. However, the functions of these two proteins during spermatogenesis in nonmammalian species, especially Crustacea, are still unknown. Here, we cloned es-Arp3 and es-Eps8 from the testis of Chinese mitten crab Eriocheir sinensis. es-Arp3 and es-Eps8 were located in spermatocytes, spermatids and spermatozoa. Knockdown of es-Arp3 and es-Eps8 in vivo caused morphological changes to seminiferous tubules including delayed spermatozoa release, shedding of germ cells and vacuoles. Filamentous-actin (F-actin) filaments network was disorganized due to deficiency of es-Arp3 and es-Eps8. Accompanying this, four junctional proteins (α-catenin, β-catenin, pinin and ZO1) displayed abnormal expression levels as well as penetrating biotin signals in seminiferous tubules. We also used the Arp2/3 complex inhibitor CK666 to block es-Arp3 activity and supported es-Arp3 knockdown results. In summary, our study demonstrated for the first time that es-Arp3 and es-Eps8 are important for spermatogenesis via regulating microfilament-mediated cell adhesion in Eriocheir sinensis.
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Affiliation(s)
- Jia-Ming Wang
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhen-Fang Li
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Hong-Yu Qi
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhan Zhao
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Wan-Xi Yang
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
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Campellone KG, Lebek NM, King VL. Branching out in different directions: Emerging cellular functions for the Arp2/3 complex and WASP-family actin nucleation factors. Eur J Cell Biol 2023; 102:151301. [PMID: 36907023 DOI: 10.1016/j.ejcb.2023.151301] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 02/07/2023] [Accepted: 02/25/2023] [Indexed: 03/06/2023] Open
Abstract
The actin cytoskeleton impacts practically every function of a eukaryotic cell. Historically, the best-characterized cytoskeletal activities are in cell morphogenesis, motility, and division. The structural and dynamic properties of the actin cytoskeleton are also crucial for establishing, maintaining, and changing the organization of membrane-bound organelles and other intracellular structures. Such activities are important in nearly all animal cells and tissues, although distinct anatomical regions and physiological systems rely on different regulatory factors. Recent work indicates that the Arp2/3 complex, a broadly expressed actin nucleator, drives actin assembly during several intracellular stress response pathways. These newly described Arp2/3-mediated cytoskeletal rearrangements are coordinated by members of the Wiskott-Aldrich Syndrome Protein (WASP) family of actin nucleation-promoting factors. Thus, the Arp2/3 complex and WASP-family proteins are emerging as crucial players in cytoplasmic and nuclear activities including autophagy, apoptosis, chromatin dynamics, and DNA repair. Characterizations of the functions of the actin assembly machinery in such stress response mechanisms are advancing our understanding of both normal and pathogenic processes, and hold great promise for providing insights into organismal development and interventions for disease.
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Affiliation(s)
- Kenneth G Campellone
- Department of Molecular and Cell Biology, Institute for Systems Genomics; University of Connecticut; Storrs, CT, USA.
| | - Nadine M Lebek
- Department of Molecular and Cell Biology, Institute for Systems Genomics; University of Connecticut; Storrs, CT, USA
| | - Virginia L King
- Department of Molecular and Cell Biology, Institute for Systems Genomics; University of Connecticut; Storrs, CT, USA
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Su L, Liu Y, Ma H, Zheng F, Daia Y, Wang T, Wang G, Li F, Zhang Y, Yu B, Gong S, Kou J. YiQiFuMai lyophilized injection attenuates cerebral ischemic injury with inhibition of neuronal autophagy through intervention in the NMMHC IIA-actin-ATG9A interaction. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2022; 95:153882. [PMID: 34968897 DOI: 10.1016/j.phymed.2021.153882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 11/30/2021] [Accepted: 12/03/2021] [Indexed: 06/14/2023]
Abstract
BACKGROUND YiQiFuMai lyophilized injection (YQFM) is derived from a traditional Chinese medicine prescription termed Shengmai San.YQFM is clinically applied to the treatment of cardiovascular and cerebrovascular diseases. It has been found that critical components of YQFM affect non-muscle myosin heavy chain IIA (NMMHC IIA), but its regulation in the excessive autophagy and the underlying mechanism has yet to be clarified. PURPOSE To evaluate whether YQFM has neuroprotective effects on cerebral ischemia/reperfusion-induced injury by inhibiting NMMHC IIA-actin-ATG9A interaction for autophagosome formation. METHODS The neuroprotective effects of YQFM were investigated in vivo in mice with middle cerebral artery occlusion/reperfusion (MCAO/R) (n = 6) by detecting neurological deficits, infarct volume, and histopathological changes. The NMMHC IIA-actin-ATG9A interaction was determined using immunofluorescence co-localization, co-immunoprecipitation, and proximity ligation assay. Rat pheochromocytoma (PC12) cells subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) were used to mimic neurons in in vitro experiments. RESULTS In MCAO/R model mice, YQFM (1.342 g/kg) attenuated brain ischemia/reperfusion-induced injury by regulating NMMHC IIA-actin-mediated ATG9A trafficking. YQFM (400 μg/ml) also exerted similar effects on OGD/R-induced PC12 cells. Furthermore, RNAi of NMMHC IIA weakened the NMMHC IIA-F-actin-dependent ATG9A trafficking and, therefore, attenuated the neuroprotective activities of YQFM in vitro. CONCLUSION These findings demonstrated that YQFM exerted neuroprotective effects by regulating the NMMHC IIA-actin-ATG9A interaction for autophagosome formation. This evidence sheds new light on the potential mechanism of YQFM in the treatment of cerebral ischemia/reperfusion.
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Affiliation(s)
- Linjie Su
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198 China
| | - Yining Liu
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198 China
| | - Huifen Ma
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198 China
| | - Fan Zheng
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198 China
| | - Yujie Daia
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198 China
| | - Tiezheng Wang
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198 China
| | - Guangyun Wang
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198 China
| | - Fang Li
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198 China
| | - Yuanyuan Zhang
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198 China
| | - Boyang Yu
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Resource and Developmemt of Chinese Material Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198 China
| | - Shuaishuai Gong
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198 China.
| | - Junping Kou
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198 China.
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14
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Shen T, Jiang L, Wang X, Xu Q, Han L, Liu S, Huang T, Li H, Dai L, Li H, Lu K. Function and molecular mechanism of N-terminal acetylation in autophagy. Cell Rep 2021; 37:109937. [PMID: 34788606 DOI: 10.1016/j.celrep.2021.109937] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 08/16/2021] [Accepted: 10/12/2021] [Indexed: 02/08/2023] Open
Abstract
Acetyl ligation to the amino acids in a protein is an important posttranslational modification. However, in contrast to lysine acetylation, N-terminal acetylation is elusive in terms of its cellular functions. Here, we identify Nat3 as an N-terminal acetyltransferase essential for autophagy, a catabolic pathway for bulk transport and degradation of cytoplasmic components. We identify the actin cytoskeleton constituent Act1 and dynamin-like GTPase Vps1 (vacuolar protein sorting 1) as substrates for Nat3-mediated N-terminal acetylation of the first methionine. Acetylated Act1 forms actin filaments and therefore promotes the transport of Atg9 vesicles for autophagosome formation; acetylated Vps1 recruits and facilitates bundling of the SNARE (soluble N-ethylmaleimide-sensitive factor activating protein receptor) complex for autophagosome fusion with vacuoles. Abolishment of the N-terminal acetylation of Act1 and Vps1 is associated with blockage of upstream and downstream steps of the autophagy process. Therefore, our work shows that protein N-terminal acetylation plays a critical role in controlling autophagy by fine-tuning multiple steps in the process.
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Affiliation(s)
- Tianyun Shen
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and The Research Units of West China, Chinese Academy of Medical Sciences, Chengdu 610041, China
| | - Lan Jiang
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and The Research Units of West China, Chinese Academy of Medical Sciences, Chengdu 610041, China
| | - Xinyuan Wang
- National Clinical Research Center for Geriatrics and Department of General Practice, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, China
| | - Qingjia Xu
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and The Research Units of West China, Chinese Academy of Medical Sciences, Chengdu 610041, China
| | - Lu Han
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and The Research Units of West China, Chinese Academy of Medical Sciences, Chengdu 610041, China
| | - Shiyan Liu
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and The Research Units of West China, Chinese Academy of Medical Sciences, Chengdu 610041, China
| | - Ting Huang
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and The Research Units of West China, Chinese Academy of Medical Sciences, Chengdu 610041, China
| | - Hongyan Li
- Department of General Surgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Lunzhi Dai
- National Clinical Research Center for Geriatrics and Department of General Practice, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, China.
| | - Huihui Li
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and The Research Units of West China, Chinese Academy of Medical Sciences, Chengdu 610041, China; West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041, China.
| | - Kefeng Lu
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and The Research Units of West China, Chinese Academy of Medical Sciences, Chengdu 610041, China.
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15
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Hernández-Cáceres MP, Munoz L, Pradenas JM, Pena F, Lagos P, Aceiton P, Owen GI, Morselli E, Criollo A, Ravasio A, Bertocchi C. Mechanobiology of Autophagy: The Unexplored Side of Cancer. Front Oncol 2021; 11:632956. [PMID: 33718218 PMCID: PMC7952994 DOI: 10.3389/fonc.2021.632956] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 02/01/2021] [Indexed: 12/12/2022] Open
Abstract
Proper execution of cellular function, maintenance of cellular homeostasis and cell survival depend on functional integration of cellular processes and correct orchestration of cellular responses to stresses. Cancer transformation is a common negative consequence of mismanagement of coordinated response by the cell. In this scenario, by maintaining the balance among synthesis, degradation, and recycling of cytosolic components including proteins, lipids, and organelles the process of autophagy plays a central role. Several environmental stresses activate autophagy, among those hypoxia, DNA damage, inflammation, and metabolic challenges such as starvation. In addition to these chemical challenges, there is a requirement for cells to cope with mechanical stresses stemming from their microenvironment. Cells accomplish this task by activating an intrinsic mechanical response mediated by cytoskeleton active processes and through mechanosensitive protein complexes which interface the cells with their mechano-environment. Despite autophagy and cell mechanics being known to play crucial transforming roles during oncogenesis and malignant progression their interplay is largely overlooked. In this review, we highlight the role of physical forces in autophagy regulation and their potential implications in both physiological as well as pathological conditions. By taking a mechanical perspective, we wish to stimulate novel questions to further the investigation of the mechanical requirements of autophagy and appreciate the extent to which mechanical signals affect this process.
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Affiliation(s)
- Maria Paz Hernández-Cáceres
- Laboratory of Autophagy and Metabolism, Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica De Chile, Santiago, Chile
| | - Leslie Munoz
- Laboratory for Mechanobiology of Transforming Systems, Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- Laboratory for Molecular Mechanics of Cell Adhesion, Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica De Chile, Santiago, Chile
| | - Javiera M. Pradenas
- Advanced Center for Chronic Diseases (ACCDiS), Santiago, Chile
- Laboratory of Investigation in Oncology, Faculty of Biological Sciences Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Francisco Pena
- Laboratory for Mechanobiology of Transforming Systems, Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- Laboratory for Molecular Mechanics of Cell Adhesion, Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica De Chile, Santiago, Chile
| | - Pablo Lagos
- Laboratory of Autophagy and Metabolism, Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica De Chile, Santiago, Chile
| | - Pablo Aceiton
- Laboratory for Mechanobiology of Transforming Systems, Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- Laboratory for Molecular Mechanics of Cell Adhesion, Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica De Chile, Santiago, Chile
| | - Gareth I. Owen
- Advanced Center for Chronic Diseases (ACCDiS), Santiago, Chile
- Laboratory of Investigation in Oncology, Faculty of Biological Sciences Pontificia Universidad Católica de Chile, Santiago, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
| | - Eugenia Morselli
- Laboratory of Autophagy and Metabolism, Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica De Chile, Santiago, Chile
- Autophagy Research Center, Santiago de Chile, Chile
| | - Alfredo Criollo
- Advanced Center for Chronic Diseases (ACCDiS), Santiago, Chile
- Autophagy Research Center, Santiago de Chile, Chile
- Facultad De Odontología, Instituto De Investigación En Ciencias Odontológicas (ICOD), Universidad De Chile, Santiago, Chile
| | - Andrea Ravasio
- Laboratory for Mechanobiology of Transforming Systems, Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Cristina Bertocchi
- Laboratory for Molecular Mechanics of Cell Adhesion, Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica De Chile, Santiago, Chile
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16
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Zhang H, Zhao Y, Yao Q, Ye Z, Mañas A, Xiang J. Ubl4A is critical for mitochondrial fusion process under nutrient deprivation stress. PLoS One 2020; 15:e0242700. [PMID: 33211772 PMCID: PMC7676689 DOI: 10.1371/journal.pone.0242700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 11/08/2020] [Indexed: 01/10/2023] Open
Abstract
Mitochondrial fusion and fission are dynamic processes regulated by the cellular microenvironment. Under nutrient starvation conditions, mitochondrial fusion is strengthened for energy conservation. We have previously shown that newborns of Ubl4A-deficient mice were more sensitive to starvation stress with a higher rate of mortality than their wild-type littermates. Ubl4A binds with the actin-related protein Arp2/3 complex to synergize the actin branching process. Here, we showed that deficiency in Ubl4A resulted in mitochondrial fragmentation and apoptosis. A defect in the fusion process was the main cause of the mitochondrial fragmentation and resulted from a shortage of primed Arp2/3 complex pool around the mitochondria in the Ubl4A-deficient cells compared to the wild-type cells. As a result, the mitochondrial fusion process was not undertaken quickly enough to sustain starvation stress-induced cell death. Consequently, fragmented mitochondria lost their membrane integrity and ROS was accumulated to trigger caspase 9-dependent apoptosis before autophagic rescue. Furthermore, the wild-type Ubl4A, but not the Arp2/3-binding deficient mutant, could rescue the starvation-induced mitochondrial fragmentation phenotype. These results suggest that Ubl4A promotes the mitochondrial fusion process via Arp2/3 complex during the initial response to nutrient deprivation for cell survival.
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Affiliation(s)
- Huaiyuan Zhang
- Department of Biology, Illinois Institute of Technology, Chicago, IL, United States of America
| | - Yu Zhao
- Department of Biology, Illinois Institute of Technology, Chicago, IL, United States of America
| | - Qi Yao
- Department of Biology, Illinois Institute of Technology, Chicago, IL, United States of America
| | - Zijing Ye
- Department of Biology, Illinois Institute of Technology, Chicago, IL, United States of America
| | - Adriana Mañas
- Department of Biology, Illinois Institute of Technology, Chicago, IL, United States of America
| | - Jialing Xiang
- Department of Biology, Illinois Institute of Technology, Chicago, IL, United States of America
- * E-mail:
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17
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Wang P, Gao E, Hussey PJ. Autophagosome Biogenesis in Plants: An Actin Cytoskeleton Perspective. TRENDS IN PLANT SCIENCE 2020; 25:850-858. [PMID: 32345568 DOI: 10.1016/j.tplants.2020.03.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/24/2020] [Accepted: 03/30/2020] [Indexed: 06/11/2023]
Abstract
At the subcellular level, the cytoskeleton regulates cell structure, organelle movement, and cytoplasmic streaming. Autophagy is a process to remove unwanted biomaterials or damaged organelles through double membrane compartments known as autophagosomes. Autophagosome biogenesis requires vesicle trafficking between donor and acceptor compartments, membrane expansion, and fusion, which is very likely to be regulated by the cytoskeleton. Recent studies have demonstrated that by knocking out key actin-regulating proteins, autophagosome biogenesis is inhibited. However, the formation of ATG8 positive structures are not affected when the entire actin network is disrupted. Here, we discuss this paradox and propose the function of the actin cytoskeleton in plant autophagy.
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Affiliation(s)
- Pengwei Wang
- Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, Hubei Province, PR China.
| | - Erlin Gao
- Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, Hubei Province, PR China
| | - Patrick J Hussey
- Department of Biosciences, Durham University, South Road, Durham, DH1 3LE, UK; Department of Experimental Plant Biology, Charles University, Faculty of Science, Viničná 5, CZ 128 43 Praha 2, Czechia.
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18
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Wang G, Wang T, Hu Y, Wang J, Wang Y, Zhang Y, Li F, Liu W, Sun Y, Yu B, Kou J. NMMHC IIA triggers neuronal autophagic cell death by promoting F-actin-dependent ATG9A trafficking in cerebral ischemia/reperfusion. Cell Death Dis 2020; 11:428. [PMID: 32513915 PMCID: PMC7280511 DOI: 10.1038/s41419-020-2639-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 05/22/2020] [Accepted: 05/25/2020] [Indexed: 12/13/2022]
Abstract
Previous findings have shown that non-muscle myosin heavy-chain IIA (NMMHC IIA) is involved in autophagy induction triggered by starvation in D. melanogaster; however, its functional contribution to neuronal autophagy remains unclear. The aim of this study is to explore the function of NMMHC IIA in cerebral ischemia-induced neuronal autophagy and the underlying mechanism related to autophagy-related gene 9A (ATG9A) trafficking. Functional assays and molecular mechanism studies were used to investigate the role of NMMHC IIA in cerebral ischemia-induced neuronal autophagy in vivo and in vitro. A middle cerebral artery occlusion (MCAO) model in mice was used to evaluate the therapeutic effect of blebbistatin, a myosin II ATPase inhibitor. Herein, either depletion or knockdown of NMMHC IIA led to increased cell viability in both primary cultured cortical neurons and pheochromocytoma (PC12) cells exposed to oxygen–glucose deprivation/reoxygenation (OGD/R). In addition, NMMHC IIA and autophagic marker LC3B were upregulated by OGD/R, and inhibition of NMMHC IIA significantly reduced OGD-induced neuronal autophagy. Furthermore, NMMHC IIA-induced autophagy is through its interactions with F-actin and ATG9A in response to OGD/R. The NMMHC IIA–actin interaction contributes to ATG9A trafficking and autophagosome formation. Inhibition of the NMMHC IIA–actin interaction using blebbistatin and the F-actin polymerization inhibitor cytochalasin D significantly suppressed ATG9A trafficking and autophagy induction. Furthermore, blebbistatin significantly improved neurological deficits and infarct volume after ischemic attack in mice, accompanied by ATG9A trafficking and autophagy inhibition. These findings demonstrate neuroprotective effects of NMMHC IIA inhibition on regulating ATG9A trafficking-dependent autophagy activation in the context of cerebral ischemia/reperfusion.
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Affiliation(s)
- Guangyun Wang
- State Key Laboratory of Natural Products, Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Material Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, 211198, China
| | - Tiezheng Wang
- State Key Laboratory of Natural Products, Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Material Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, 211198, China
| | - Yang Hu
- State Key Laboratory of Natural Products, Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Material Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, 211198, China
| | - Jieman Wang
- State Key Laboratory of Natural Products, Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Material Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, 211198, China
| | - Yan Wang
- Department of Neurology, University of California, Davis, School of Medicine and Shriners Hospital, Sacramento, CA, 95817, Berkeley, USA
| | - Yuanyuan Zhang
- State Key Laboratory of Natural Products, Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Material Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, 211198, China
| | - Fang Li
- State Key Laboratory of Natural Products, Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Material Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, 211198, China
| | - Wentao Liu
- Department of Pharmacology, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, 210029, China
| | - Yang Sun
- State Key Laboratory of Pharmaceutical Biotechnology, Deparment of Biotechnology and Pharmaceutical Sciences, School of Life Sciences, Nanjing University, Nanjing, 210023, China
| | - Boyang Yu
- State Key Laboratory of Natural Products, Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Resource and Developmemt of Chinese Material Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, 211198, China.
| | - Junping Kou
- State Key Laboratory of Natural Products, Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Material Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, 211198, China.
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Zheng X, Wu M, Li X, Cao J, Li J, Wang J, Huang S, Liu Y, Wang Y. Actin filaments are dispensable for bulk autophagy in plants. Autophagy 2019; 15:2126-2141. [PMID: 30907219 PMCID: PMC6844523 DOI: 10.1080/15548627.2019.1596496] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 02/27/2019] [Accepted: 03/01/2019] [Indexed: 10/27/2022] Open
Abstract
Actin filament, also known as microfilament, is one of two major cytoskeletal elements in plants and plays important roles in various biological processes. Like in animal cells, actin filaments have been thought to participate in autophagy in plants. However, surprisingly, in this study we found that actin filaments are dispensable for the occurrence of autophagy in plants. Disruption of actin filaments by short term treatment with actin polymerization inhibitors, cytochalasin D and latrunculin B, or transient overexpression of Profilin 3 in Nicotiana benthamiana had no effect on basal autophagy as well as the upregulation of nocturnal autophagy and salt stress-induced autophagy. Furthermore, anti-microfilament drug treatment affected neither basal nor salt stress-induced autophagy in Arabidopsis. In addition, prolonged perturbation of actin filaments by silencing Actin7 or 24-h treatment with microfilament-disrupting agents in N. benthamiana caused endoplasmic reticulum (ER) disorganization and subsequent degradation via autophagy involving ATG2, 3, 5, 6 and 7. Our findings reveal that, unlike mammalian cells, actin filaments are unnecessary for bulk autophagy in plants.Abbreviations: ATG: autophagy-related; CD: cytochalasin D; Cvt pathway: cytoplasm to vacuole targeting pathway; DMSO: dimethyl sulfoxide; ER: endoplasmic reticulum; LatB: latrunculin B; Nb: Nicotiana benthamiana; PAS: phagophore assembly site; PRF3: Profilin 3; RER: rough ER; SER: smooth ER; TEM: transmission electron microscopy; TRV: Tobacco rattle virus; VIGS: virus-induced gene silencing; wpi: weeks post-agroinfiltration.
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Affiliation(s)
- Xiyin Zheng
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Ming Wu
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xinyi Li
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jidong Cao
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jinlin Li
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jieling Wang
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yule Liu
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yan Wang
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
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Macharia MW, Tan WYZ, Das PP, Naqvi NI, Wong SM. Proximity-dependent biotinylation screening identifies NbHYPK as a novel interacting partner of ATG8 in plants. BMC PLANT BIOLOGY 2019; 19:326. [PMID: 31324141 PMCID: PMC6642529 DOI: 10.1186/s12870-019-1930-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 07/09/2019] [Indexed: 05/27/2023]
Abstract
BACKGROUND Autophagy is a conserved, highly-regulated catabolic process that plays important roles in growth, development and innate immunity in plants. In this study, we compared the rate of autophagy induction in Nicotiana benthamiana plants infected with Tobacco mosaic virus or the TMV 24A + UPD mutant variant, which replicates at a faster rate and induces more severe symptoms. Using a BirA* tag and proximity-dependent biotin identification (BioID) analysis, we identified host proteins that interact with the core autophagy protein, ATG8 in TMV 24A + UPD infected plants. By combining the use of a fast replicating TMV mutant and an in vivo protein-protein screening technique, we were able to gain functional insight into the role of autophagy in a compatible virus-host interaction. RESULTS Our study revealed an increased autophagic flux induced by TMV 24A + UPD, as compared to TMV in N. benthamiana. Analysis of the functional proteome associated with ATG8 revealed a total of 67 proteins, 16 of which are known to interact with ATG8 or its orthologs in mammalian and yeast systems. The interacting proteins were categorized into four functional groups: immune system process, response to ROS, sulphur amino acid metabolism and calcium signalling. Due to the presence of an ubiquitin-associated (UBA) domain, which is demonstrated to interact with ATG8, the Huntingtin-interacting protein K-like (HYPK) was selected for validation of the physical interaction and function. We used yeast two hybrid (Y2H), bimolecular fluorescence complementation (BiFC) and subcellular localization to validate the ATG8-HYPK interaction. Subsequent down-regulation of ATG8 by virus-induced gene silencing (VIGS) showed enhanced TMV symptoms, suggesting a protective role for autophagy during TMV 24A + UPD infection. CONCLUSION This study presents the use of BioID as a suitable method for screening ATG8 interacting proteins in planta. We have identified many putative binding partners of ATG8 during TMV 24A + UPD infection in N. benthamiana plants. In addition, we have verified that NbHYPK is an interacting partner of ATG8. We infer that autophagy plays a protective role in TMV 24A + UPD infected plants.
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Affiliation(s)
- Mercy W Macharia
- Department of Biological Sciences, National University of Singapore, Singapore, 119543, Singapore
| | - Wilfred Y Z Tan
- Department of Biological Sciences, National University of Singapore, Singapore, 119543, Singapore
| | - Prem P Das
- Department of Biological Sciences, National University of Singapore, Singapore, 119543, Singapore
| | - Naweed I Naqvi
- Department of Biological Sciences, National University of Singapore, Singapore, 119543, Singapore
- Temasek Life Sciences Laboratory, Singapore, 117604, Singapore
| | - Sek-Man Wong
- Department of Biological Sciences, National University of Singapore, Singapore, 119543, Singapore.
- Temasek Life Sciences Laboratory, Singapore, 117604, Singapore.
- National University of Singapore Research Institute, Suzhou, Jiangsu, 215123, People's Republic of China.
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21
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Izdebska M, Hałas-Wiśniewska M, Zielińska W, Klimaszewska-Wiśniewska A, Grzanka D, Gagat M. Lidocaine induces protective autophagy in rat C6 glioma cell line. Int J Oncol 2018; 54:1099-1111. [PMID: 30569147 PMCID: PMC6365045 DOI: 10.3892/ijo.2018.4668] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/16/2018] [Indexed: 02/06/2023] Open
Abstract
Malignant glioma is the most common type of brain cancer with poor prognosis. Surgical resection, chemotherapy and radiotherapy are the main therapeutic options; however, in addition to their insufficient efficacy, they are associated with the pain experienced by patients. To relieve pain, local anesthetics, such as lidocaine can be used. In the present study, the effects of lidocaine on the C6 rat glioma cell line were investigated. An MTT assay and Annexin V/propidium iodide analysis indicated the increase in the percentage of apoptotic and necrotic cells in response to lidocaine. Furthermore, light microscopy analysis on the ultrastructural level presented the occurrence of vacuole-like structures associated with autophagy, which was supported by the analysis of autophagy markers (microtubule-associated protein 1A/1B-light chain 3, acridine orange and Beclin-1). Additionally, reorganization of the cytoskeleton was observed following treatment with lidocaine, which serves an important role in the course of autophagy. To determine the nature of autophagy, an inhibitor, bafilomycin A1 was applied. This compound suppressed the fusion of autophagosomes with lysosomes and increased the percentage of apoptotic cells. These results demonstrated that lidocaine may induce cytoprotective autophagy and that manipulation of this process could be an alternative therapeutic strategy in the treatment of cancer.
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Affiliation(s)
- Magdalena Izdebska
- Department of Histology and Embryology, Faculty of Medicine, Nicolaus Copernicus University in Toruń, Collegium Medicum in Bydgoszcz, 85-092 Bydgoszcz, Poland
| | - Marta Hałas-Wiśniewska
- Department of Histology and Embryology, Faculty of Medicine, Nicolaus Copernicus University in Toruń, Collegium Medicum in Bydgoszcz, 85-092 Bydgoszcz, Poland
| | - Wioletta Zielińska
- Department of Histology and Embryology, Faculty of Medicine, Nicolaus Copernicus University in Toruń, Collegium Medicum in Bydgoszcz, 85-092 Bydgoszcz, Poland
| | - Anna Klimaszewska-Wiśniewska
- Department of Clinical Pathomorphology, Faculty of Medicine, Nicolaus Copernicus University in Toruń, Collegium Medicum in Bydgoszcz, 85-092 Bydgoszcz, Poland
| | - Dariusz Grzanka
- Department of Clinical Pathomorphology, Faculty of Medicine, Nicolaus Copernicus University in Toruń, Collegium Medicum in Bydgoszcz, 85-092 Bydgoszcz, Poland
| | - Maciej Gagat
- Department of Histology and Embryology, Faculty of Medicine, Nicolaus Copernicus University in Toruń, Collegium Medicum in Bydgoszcz, 85-092 Bydgoszcz, Poland
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22
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Abstract
Recent publications illustrate an extensive crosstalk between the actin cytoskeleton and autophagy, a program for self-digestion. Actin polymerization provides a pushing force for organelle shaping and trafficking during autophagy, but the cytoskeleton is also targeted by autophagy under mechanical strain.
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Affiliation(s)
- Jörg Höhfeld
- Institute for Cell Biology, University of Bonn, Bonn, Germany.
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23
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Wang P, Hawkins TJ, Hussey PJ. Connecting membranes to the actin cytoskeleton. CURRENT OPINION IN PLANT BIOLOGY 2017; 40:71-76. [PMID: 28779654 DOI: 10.1016/j.pbi.2017.07.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/13/2017] [Indexed: 05/10/2023]
Abstract
In plants, the actin cytoskeleton plays a major role in organelle movement, cargo transport, maintaining cell polarity and controlling the morphogenesis of endomembrane systems. All of these events require a direct connection between membrane structures and the cytoskeleton. Our knowledge in this field has been greatly advanced by a few recent discoveries including the identification of the plant specific NETWORKED family of proteins, which can mediate such linkages. Other proteins that are known to regulate actin nucleation and polymerization are also likely to be involved, but many key questions still remain unanswered. In this paper, we will focus on recent research on the interfaces between the actin cytoskeleton and membranes of the endoplasmic reticulum, the vacuole and autophagosomes.
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Affiliation(s)
- Pengwei Wang
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK; Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, Hubei Province, PR China
| | - Tim J Hawkins
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
| | - Patrick J Hussey
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK.
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24
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Nozawa T, Aikawa C, Minowa-Nozawa A, Nakagawa I. The intracellular microbial sensor NLRP4 directs Rho-actin signaling to facilitate Group A Streptococcus-containing autophagosome-like vacuole formation. Autophagy 2017; 13:1841-1854. [PMID: 29099277 PMCID: PMC5788493 DOI: 10.1080/15548627.2017.1358343] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 06/30/2017] [Accepted: 07/18/2017] [Indexed: 12/19/2022] Open
Abstract
Xenophagy, also known as antibacterial autophagy, functions as a crucial defense system that can utilize intracellular pattern recognition sensors, such as NLRP4, to recognize and selectively eliminate bacterial pathogens. However, little is known about how NLRP4 regulates xenophagy. Here, we report that NLRP4 binds ARHGDIA (Rho GDP dissociation inhibitor α) to regulate Rho GTPase signaling and facilitate actin-mediated xenophagy. Specifically, NLRP4 is recruited to Group A Streptococcus (GAS) and colocalizes with GAS-containing autophagosome-like vacuoles (GcAVs), where it regulates ARHGDIA-Rho GTPase recruitment to promote autophagosome formation. The interaction between NLRP4, ARHGDIA, and Rho GTPases is regulated by ARHGDIA Tyr156 phosphorylation, which acts as a gate to induce Rho-mediated xenophagy. Moreover, ARHGDIA and Rho GTPase are involved in actin-mediated ATG9A recruitment to phagophores, facilitating elongation to form autophagosomes. Collectively, these findings demonstrate that NLRP4 functions as a Rho receptor complex to direct actin dynamics regulating xenophagy.
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Affiliation(s)
- Takashi Nozawa
- Department of Microbiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Chihiro Aikawa
- Department of Microbiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Atsuko Minowa-Nozawa
- Department of Microbiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Ichiro Nakagawa
- Department of Microbiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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25
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Zientara-Rytter K, Sirko A. To deliver or to degrade - an interplay of the ubiquitin-proteasome system, autophagy and vesicular transport in plants. FEBS J 2017; 283:3534-3555. [PMID: 26991113 DOI: 10.1111/febs.13712] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 02/21/2016] [Accepted: 03/14/2016] [Indexed: 12/21/2022]
Abstract
The efficient utilization and subsequent reuse of cell components is a key factor in determining the proper growth and functioning of all cells under both optimum and stress conditions. The process of intracellular and intercellular recycling is especially important for the appropriate control of cellular metabolism and nutrient management in immobile organisms, such as plants. Therefore, the accurate recycling of amino acids, lipids, carbohydrates or micro- and macronutrients available in the plant cell becomes a critical factor that ensures plant survival and growth. Plant cells possess two main degradation mechanisms: a ubiquitin-proteasome system and autophagy, which, as a part of an intracellular trafficking system, is based on vesicle transport. This review summarizes knowledge of both the ubiquitin-proteasome system and autophagy pathways, describes the cross-talk between the two and discusses the relationships between autophagy and the vesicular transport systems.
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Affiliation(s)
| | - Agnieszka Sirko
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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26
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Kumar R, Neuser N, Tyedmers J. Hitchhiking vesicular transport routes to the vacuole: Amyloid recruitment to the Insoluble Protein Deposit (IPOD). Prion 2017; 11:71-81. [PMID: 28277942 PMCID: PMC5399893 DOI: 10.1080/19336896.2017.1293226] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sequestration of aggregates into specialized deposition sites occurs in many species across all kingdoms of life ranging from bacteria to mammals and is commonly believed to have a cytoprotective function. Yeast cells possess at least 3 different spatially separated deposition sites, one of which is termed “Insoluble Protein Deposit (IPOD)” and harbors amyloid aggregates. We have recently discovered that recruitment of amyloid aggregates to the IPOD uses an actin cable based recruitment machinery that also involves vesicular transport.1 Here we discuss how different proteins known to be involved in vesicular transport processes to the vacuole might act to guide amyloid aggregates to the IPOD. These factors include the Myosin V motor protein Myo2 involved in transporting vacuolar vesicles along actin cables, the transmembrane protein Atg9 involved in the recruitment of large precursor hydrolase complexes to the vacuole, the phosphatidylinositol/ phosphatidylcholine (PI/PC) transfer protein Sec 14 and the SNARE chaperone Sec 18. Furthermore, we present new data suggesting that the yeast dynamin homolog Vps1 is also crucial for faithful delivery of the amyloid model protein PrD-GFP to the IPOD. This is in agreement with a previously identified role for Vps1 in recruitment of heat-denatured aggregates to a perivacuolar deposition site.2
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Affiliation(s)
- Rajesh Kumar
- a Department of Medicine I and Clinical Chemistry , University Hospital Heidelberg , Heidelberg , Germany
| | - Nicole Neuser
- a Department of Medicine I and Clinical Chemistry , University Hospital Heidelberg , Heidelberg , Germany
| | - Jens Tyedmers
- a Department of Medicine I and Clinical Chemistry , University Hospital Heidelberg , Heidelberg , Germany
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27
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Prion Aggregates Are Recruited to the Insoluble Protein Deposit (IPOD) via Myosin 2-Based Vesicular Transport. PLoS Genet 2016; 12:e1006324. [PMID: 27689885 PMCID: PMC5045159 DOI: 10.1371/journal.pgen.1006324] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Accepted: 08/25/2016] [Indexed: 12/31/2022] Open
Abstract
Aggregation of amyloidogenic proteins is associated with several neurodegenerative diseases. Sequestration of misfolded and aggregated proteins into specialized deposition sites may reduce their potentially detrimental properties. Yeast exhibits a distinct deposition site for amyloid aggregates termed "Insoluble PrOtein Deposit (IPOD)", but nothing is known about the mechanism of substrate recruitment to this site. The IPOD is located directly adjacent to the Phagophore Assembly Site (PAS) where the cell initiates autophagy and the Cytoplasm-to-Vacuole Targeting (CVT) pathway destined for delivery of precursor peptidases to the vacuole. Recruitment of CVT substrates to the PAS was proposed to occur via vesicular transport on Atg9 vesicles and requires an intact actin cytoskeleton and "SNAP (Soluble NSF Attachment Protein) Receptor Proteins (SNARE)" protein function. It is, however, unknown how this vesicular transport machinery is linked to the actin cytoskeleton. We demonstrate that recruitment of model amyloid PrD-GFP and the CVT substrate precursor-aminopeptidase 1 (preApe1) to the IPOD or PAS, respectively, is disturbed after genetic impairment of Myo2-based actin cable transport and SNARE protein function. Rather than accumulating at the respective deposition sites, both substrates reversibly accumulated often together in the same punctate structures. Components of the CVT vesicular transport machinery including Atg8 and Atg9 as well as Myo2 partially co-localized with the joint accumulations. Thus we propose a model where vesicles, loaded with preApe1 or PrD-GFP, are recruited to tropomyosin coated actin cables via the Myo2 motor protein for delivery to the PAS and IPOD, respectively. We discuss that deposition at the IPOD is not an integrated mandatory part of the degradation pathway for amyloid aggregates, but more likely stores excess aggregates until downstream degradation pathways have the capacity to turn them over after liberation by the Hsp104 disaggregation machinery.
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28
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Farré JC, Subramani S. Mechanistic insights into selective autophagy pathways: lessons from yeast. Nat Rev Mol Cell Biol 2016; 17:537-52. [PMID: 27381245 PMCID: PMC5549613 DOI: 10.1038/nrm.2016.74] [Citation(s) in RCA: 300] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Autophagy has burgeoned rapidly as a field of study because of its evolutionary conservation, the diversity of intracellular cargoes degraded and recycled by this machinery, the mechanisms involved, as well as its physiological relevance to human health and disease. This self-eating process was initially viewed as a non-selective mechanism used by eukaryotic cells to degrade and recycle macromolecules in response to stress; we now know that various cellular constituents, as well as pathogens, can also undergo selective autophagy. In contrast to non-selective autophagy, selective autophagy pathways rely on a plethora of selective autophagy receptors (SARs) that recognize and direct intracellular protein aggregates, organelles and pathogens for specific degradation. Although SARs themselves are not highly conserved, their modes of action and the signalling cascades that activate and regulate them are. Recent yeast studies have provided novel mechanistic insights into selective autophagy pathways, revealing principles of how various cargoes can be marked and targeted for selective degradation.
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Affiliation(s)
- Jean-Claude Farré
- University of California, 3326 Bonner Hall, 9500 Gilman Drive, San Diego, La Jolla, California 92093-0322, USA
| | - Suresh Subramani
- University of California, 3326 Bonner Hall, 9500 Gilman Drive, San Diego, La Jolla, California 92093-0322, USA
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29
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Coutts AS, La Thangue NB. Regulation of actin nucleation and autophagosome formation. Cell Mol Life Sci 2016; 73:3249-63. [PMID: 27147468 PMCID: PMC4967107 DOI: 10.1007/s00018-016-2224-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/21/2016] [Accepted: 04/08/2016] [Indexed: 01/08/2023]
Abstract
Autophagy is a process of self-eating, whereby cytosolic constituents are enclosed by a double-membrane vesicle before delivery to the lysosome for degradation. This is an important process which allows for recycling of nutrients and cellular components and thus plays a critical role in normal cellular homeostasis as well as cell survival during stresses such as starvation or hypoxia. A large number of proteins regulate various stages of autophagy in a complex and still incompletely understood series of events. In this review, we will discuss recent studies which provide a growing body of evidence that actin dynamics and proteins that influence actin nucleation play an important role in the regulation of autophagosome formation and maturation.
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Affiliation(s)
- Amanda S Coutts
- Laboratory of Cancer Biology, Medical Sciences Division, Department of Oncology, University of Oxford, Old Road Campus Research Building, Old Road Campus, Off Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Nicholas B La Thangue
- Laboratory of Cancer Biology, Medical Sciences Division, Department of Oncology, University of Oxford, Old Road Campus Research Building, Old Road Campus, Off Roosevelt Drive, Oxford, OX3 7DQ, UK.
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30
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Smethurst DGJ, Cooper KF. ER fatalities-The role of ER-mitochondrial contact sites in yeast life and death decisions. Mech Ageing Dev 2016; 161:225-233. [PMID: 27507669 DOI: 10.1016/j.mad.2016.07.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 06/22/2016] [Accepted: 07/19/2016] [Indexed: 12/22/2022]
Abstract
Following extracellular stress signals, all eukaryotic cells choose whether to elicit a pro-survival or pro-death response. The decision over which path to take is governed by the severity and duration of the damage. In response to mild stress, pro-survival programs are initiated (unfolded protein response, autophagy, mitophagy) whereas severe or chronic stress forces the cell to abandon these adaptive programs and shift towards regulated cell death to remove irreversibly damaged cells. Both pro-survival and pro-death programs involve regulated communication between the endoplasmic reticulum (ER) and mitochondria. In yeast, recent data suggest this inter-organelle contact is facilitated by the endoplasmic reticulum mitochondria encounter structure (ERMES). These membrane contacts are not only important for the exchange of cellular signals, but also play a role in mitochondrial tethering during mitophagy, mitochondrial fission and mitochondrial inheritance. This review focuses on recent findings in yeast that shed light on how ER-mitochondrial communication mediates critical cell fate decisions.
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Affiliation(s)
- Daniel G J Smethurst
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ, 08055 USA
| | - Katrina F Cooper
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ, 08055 USA.
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31
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Wang P, Richardson C, Hawes C, Hussey P. Arabidopsis NAP1 Regulates the Formation of Autophagosomes. Curr Biol 2016; 26:2060-2069. [DOI: 10.1016/j.cub.2016.06.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 05/25/2016] [Accepted: 06/06/2016] [Indexed: 01/10/2023]
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32
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Yang S, Rosenwald AG. Autophagy in Saccharomyces cerevisiae requires the monomeric GTP-binding proteins, Arl1 and Ypt6. Autophagy 2016; 12:1721-1737. [PMID: 27462928 PMCID: PMC5079543 DOI: 10.1080/15548627.2016.1196316] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Macroautophagy/autophagy is a cellular degradation process that sequesters organelles or proteins into a double-membrane structure called the phagophore; this transient compartment matures into an autophagosome, which then fuses with the lysosome or vacuole to allow hydrolysis of the cargo. Factors that control membrane traffic are also essential for each step of autophagy. Here we demonstrate that 2 monomeric GTP-binding proteins in Saccharomyces cerevisiae, Arl1 and Ypt6, which belong to the Arf/Arl/Sar protein family and the Rab family, respectively, and control endosome-trans-Golgi traffic, are also necessary for starvation-induced autophagy under high temperature stress. Using established autophagy-specific assays we found that cells lacking either ARL1 or YPT6, which exhibit synthetic lethality with one another, were unable to undergo autophagy at an elevated temperature, although autophagy proceeds normally at normal growth temperature; specifically, strains lacking one or the other of these genes are unable to construct the autophagosome because these 2 proteins are required for proper traffic of Atg9 to the phagophore assembly site (PAS) at the restrictive temperature. Using degron technology to construct an inducible arl1Δ ypt6Δ double mutant, we demonstrated that cells lacking both genes show defects in starvation-inducted autophagy at the permissive temperature. We also found Arl1 and Ypt6 participate in autophagy by targeting the Golgi-associated retrograde protein (GARP) complex to the PAS to regulate the anterograde trafficking of Atg9. Our data show that these 2 membrane traffic regulators have novel roles in autophagy.
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Affiliation(s)
- Shu Yang
- a Department of Biology , Georgetown University , Washington DC , USA
| | - Anne G Rosenwald
- a Department of Biology , Georgetown University , Washington DC , USA
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33
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Shen Y, Xia R, Jiang H, Chen Y, Hong L, Yu Y, Xu Z, Zeng Q. Exposure to 50Hz-sinusoidal electromagnetic field induces DNA damage-independent autophagy. Int J Biochem Cell Biol 2016; 77:72-79. [PMID: 27177844 DOI: 10.1016/j.biocel.2016.05.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 04/21/2016] [Accepted: 05/08/2016] [Indexed: 01/22/2023]
Abstract
As electromagnetic field (EMF) is commonly encountered within our daily lives, the biological effects of EMF are of great concern. Autophagy is a key process for maintaining cellular homeostasis, and it can also reveal cellular responses to environmental stimuli. In this study, we aim to investigate the biological effects of a 50Hz-sinusoidal electromagnetic field on autophagy and we identified its mechanism of action in Chinese Hamster Lung (CHL) cells. CHL cells were exposed to a 50Hz sinusoidal EMF at 0.4mT for 30min or 24h. In this study, we found that a 0.4mT EMF resulted in: (i) an increase in LC3-II expression and increased autophagosome formation; (ii) no significant difference in the incidence of γH2AX foci between the sham and exposure groups; (iii) reorganized actin filaments and increased pseudopodial extensions without promoting cell migration; and (iv) enhanced cell apoptosis when autophagy was blocked by Bafilomycin A1. These results implied that DNA damage was not directly involved in the autophagy induced by a 0.4mT 50Hz EMF. In addition, an EMF induced autophagy balanced the cellular homeostasis to protect the cells from severe adverse biological consequences.
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Affiliation(s)
- Yunyun Shen
- Bioelectromagnetics Laboratory, Department of Occupational and Environmental Health, School of Public Health, School of Medicine, Zhejiang University, Hangzhou 310058, PR China
| | - Ruohong Xia
- Physics Department, East China Normal University, Shanghai 200241, PR China
| | - Hengjun Jiang
- Bioelectromagnetics Laboratory, Department of Occupational and Environmental Health, School of Public Health, School of Medicine, Zhejiang University, Hangzhou 310058, PR China
| | - Yanfeng Chen
- Bioelectromagnetics Laboratory, Department of Occupational and Environmental Health, School of Public Health, School of Medicine, Zhejiang University, Hangzhou 310058, PR China
| | - Ling Hong
- Bioelectromagnetics Laboratory, Department of Occupational and Environmental Health, School of Public Health, School of Medicine, Zhejiang University, Hangzhou 310058, PR China
| | - Yunxian Yu
- Department of Epidemiology and Health Statistics, School of Public Health, School of Medicine, Zhejiang University, Hangzhou 310058, PR China
| | - Zhengping Xu
- Bioelectromagnetics Laboratory, Department of Occupational and Environmental Health, School of Public Health, School of Medicine, Zhejiang University, Hangzhou 310058, PR China.
| | - Qunli Zeng
- Bioelectromagnetics Laboratory, Department of Occupational and Environmental Health, School of Public Health, School of Medicine, Zhejiang University, Hangzhou 310058, PR China.
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34
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Vasicova P, Rinnerthaler M, Haskova D, Novakova L, Malcova I, Breitenbach M, Hasek J. Formaldehyde fixation is detrimental to actin cables in glucose-depleted S. cerevisiae cells. MICROBIAL CELL 2016; 3:206-214. [PMID: 28357356 PMCID: PMC5349148 DOI: 10.15698/mic2016.05.499] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Actin filaments form cortical patches and emanating cables in fermenting cells of
Saccharomyces cerevisiae. This pattern has been shown to be
depolarized in glucose-depleted cells after formaldehyde fixation and staining
with rhodamine-tagged phalloidin. Loss of actin cables in mother cells was
remarkable. Here we extend our knowledge on actin in live glucose-depleted cells
co-expressing the marker of actin patches (Abp1-RFP) with the marker of actin
cables (Abp140-GFP). Glucose depletion resulted in appearance of actin patches
also in mother cells. However, even after 80 min of glucose deprivation these
cells showed a clear network of actin cables labeled with Abp140-GFP in contrast
to previously published data. In live cells with a mitochondrial dysfunction
(rho0 cells), glucose depletion resulted in almost immediate
appearance of Abp140-GFP foci partially overlapping with Abp1-RFP patches in
mother cells. Residual actin cables were clustered in patch-associated bundles.
A similar overlapping “patchy” pattern of both actin markers was observed upon
treatment of glucose-deprived rho+ cells with FCCP (the inhibitor of
oxidative phosphorylation) and upon treatment with formaldehyde. While the
formaldehyde-targeted process stays unknown, our results indicate that published
data on yeast actin cytoskeleton obtained from glucose-depleted cells after
fixation should be considered with caution.
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Affiliation(s)
- Pavla Vasicova
- Laboratory of Cell Reproduction, Institute of Microbiology of the CAS, v.v.i., Prague, Czech Republic
| | - Mark Rinnerthaler
- Department of Cell Biology, Division of Genetics, University of Salzburg, Salzburg, Austria
| | - Danusa Haskova
- Laboratory of Cell Reproduction, Institute of Microbiology of the CAS, v.v.i., Prague, Czech Republic
| | - Lenka Novakova
- Laboratory of Cell Reproduction, Institute of Microbiology of the CAS, v.v.i., Prague, Czech Republic
| | - Ivana Malcova
- Laboratory of Cell Reproduction, Institute of Microbiology of the CAS, v.v.i., Prague, Czech Republic
| | - Michael Breitenbach
- Department of Cell Biology, Division of Genetics, University of Salzburg, Salzburg, Austria
| | - Jiri Hasek
- Laboratory of Cell Reproduction, Institute of Microbiology of the CAS, v.v.i., Prague, Czech Republic
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Wen X, Klionsky DJ. An overview of macroautophagy in yeast. J Mol Biol 2016; 428:1681-99. [PMID: 26908221 DOI: 10.1016/j.jmb.2016.02.021] [Citation(s) in RCA: 193] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 02/15/2016] [Accepted: 02/16/2016] [Indexed: 12/19/2022]
Abstract
Macroautophagy is an evolutionarily conserved dynamic pathway that functions primarily in a degradative manner. A basal level of macroautophagy occurs constitutively, but this process can be further induced in response to various types of stress including starvation, hypoxia and hormonal stimuli. The general principle behind macroautophagy is that cytoplasmic contents can be sequestered within a transient double-membrane organelle, an autophagosome, which subsequently fuses with a lysosome or vacuole (in mammals, or yeast and plants, respectively), allowing for degradation of the cargo followed by recycling of the resulting macromolecules. Through this basic mechanism, macroautophagy has a critical role in cellular homeostasis; however, either insufficient or excessive macroautophagy can seriously compromise cell physiology, and thus, it needs to be properly regulated. In fact, a wide range of diseases are associated with dysregulation of macroautophagy. There has been substantial progress in understanding the regulation and molecular mechanisms of macroautophagy in different organisms; however, many questions concerning some of the most fundamental aspects of macroautophagy remain unresolved. In this review, we summarize current knowledge about macroautophagy mainly in yeast, including the mechanism of autophagosome biogenesis, the function of the core macroautophagic machinery, the regulation of macroautophagy and the process of cargo recognition in selective macroautophagy, with the goal of providing insights into some of the key unanswered questions in this field.
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Affiliation(s)
- Xin Wen
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Daniel J Klionsky
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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Merched AJ, Daret D, Li L, Franzl N, Sauvage-Merched M. Specific autoantigens in experimental autoimmunity-associated atherosclerosis. FASEB J 2016; 30:2123-34. [PMID: 26891734 DOI: 10.1096/fj.201500131] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 02/01/2016] [Indexed: 12/22/2022]
Abstract
Higher cardiovascular morbidity in patients with a wide range of autoimmune diseases highlights the importance of autoimmunity in promoting atherosclerosis. Our purpose was to investigate the mechanisms of accelerated atherosclerosis and identified vascular autoantigens targeted by autoimmunity. We created a mouse model of autoimmunity-associated atherosclerosis by transplanting bone marrow from FcγRIIB knockout (FcRIIB(-/-)) mice into LDL receptor knockout mice. We characterized the cellular and molecular mechanisms of atherogenesis and identified specific aortic autoantigens using serologic proteomic studies. En face lesion area analysis showed more aggressive atherosclerosis in autoimmune mice compared with control mice (0.64 ± 0.12 vs 0.32 ± 0.05 mm(2); P < 0.05, respectively). At the cellular level, FcRIIB(-/-) macrophages showed significant reduction (46-72%) in phagocytic capabilities. Proteomic analysis revealed circulating autoantibodies in autoimmune mice that targeted 25 atherosclerotic lesion proteins, including essential components of adhesion complex, cytoskeleton, and extracellular matrix, and proteins involved in critical functions and pathways. Microscopic examination of atherosclerotic plaques revealed essential colocalization of autoantibodies with endothelial cells, their adherence to basement membranes, the internal elastica lamina, and necrotic cores. The new vascular autoimmunosome may be a useful target for diagnostic and immunotherapeutic interventions in autoimmunity-associated diseases that have accelerated atherosclerosis.-Merched, A. J., Daret, D., Li, L., Franzl, N., Sauvage-Merched, M. Specific autoantigens in experimental autoimmunity-associated atherosclerosis.
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Affiliation(s)
- Aksam J Merched
- Department of Pharmaceutical Sciences, and INSERM U1053, University of Bordeaux, Bordeaux, France Department of Cell Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Danièle Daret
- Department of Cell Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Lan Li
- Department of Cell Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Nathalie Franzl
- Department of Cell Biology, Baylor College of Medicine, Houston, Texas, USA
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Steffen A, Stradal TEB, Rottner K. Signalling Pathways Controlling Cellular Actin Organization. Handb Exp Pharmacol 2016; 235:153-178. [PMID: 27757765 DOI: 10.1007/164_2016_35] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The actin cytoskeleton is essential for morphogenesis and virtually all types of cell shape changes. Reorganization is per definition driven by continuous disassembly and re-assembly of actin filaments, controlled by major, ubiquitously operating machines. These are specifically employed by the cell to tune its activities in accordance with respective environmental conditions or to satisfy specific needs.Here we sketch some fundamental signalling pathways established to contribute to the reorganization of specific actin structures at the plasma membrane. Rho-family GTPases are at the core of these pathways, and dissection of their precise contributions to actin reorganization in different cell types and tissues will thus continue to improve our understanding of these important signalling nodes. Furthermore, we will draw your attention to the emerging theme of actin reorganization on intracellular membranes, its functional relation to Rho-GTPase signalling, and its relevance for the exciting phenomenon autophagy.
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Affiliation(s)
- Anika Steffen
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany
| | - Theresia E B Stradal
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.
| | - Klemens Rottner
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.,Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106, Braunschweig, Germany
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Harrison A, Dubois LG, St John-Williams L, Moseley MA, Hardison RL, Heimlich DR, Stoddard A, Kerschner JE, Justice SS, Thompson JW, Mason KM. Comprehensive Proteomic and Metabolomic Signatures of Nontypeable Haemophilus influenzae-Induced Acute Otitis Media Reveal Bacterial Aerobic Respiration in an Immunosuppressed Environment. Mol Cell Proteomics 2015; 15:1117-38. [PMID: 26711468 DOI: 10.1074/mcp.m115.052498] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Indexed: 12/31/2022] Open
Abstract
A thorough understanding of the molecular details of the interactions between bacteria and host are critical to ultimately prevent disease. Recent technological advances allow simultaneous analysis of host and bacterial protein and metabolic profiles from a single small tissue sample to provide insight into pathogenesis. We used the chinchilla model of human otitis media to determine, for the first time, the most expansive delineation of global changes in protein and metabolite profiles during an experimentally induced disease. After 48 h of infection with nontypeable Haemophilus influenzae, middle ear tissue lysates were analyzed by high-resolution quantitative two-dimensional liquid chromatography-tandem mass spectrometry. Dynamic changes in 105 chinchilla proteins and 66 metabolites define the early proteomic and metabolomic signature of otitis media. Our studies indicate that establishment of disease coincides with actin morphogenesis, suppression of inflammatory mediators, and bacterial aerobic respiration. We validated the observed increase in the actin-remodeling complex, Arp2/3, and experimentally showed a role for Arp2/3 in nontypeable Haemophilus influenzae invasion. Direct inhibition of actin branch morphology altered bacterial invasion into host epithelial cells, and is supportive of our efforts to use the information gathered to modify outcomes of disease. The twenty-eight nontypeable Haemophilus influenzae proteins identified participate in carbohydrate and amino acid metabolism, redox homeostasis, and include cell wall-associated metabolic proteins. Quantitative characterization of the molecular signatures of infection will redefine our understanding of host response driven developmental changes during pathogenesis. These data represent the first comprehensive study of host protein and metabolite profiles in vivo in response to infection and show the feasibility of extensive characterization of host protein profiles during disease. Identification of novel protein targets and metabolic biomarkers will advance development of therapeutic and diagnostic options for treatment of disease.
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Affiliation(s)
- Alistair Harrison
- From the ‡The Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio 43205
| | - Laura G Dubois
- ‡‡Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, Medical Center, Durham, North Carolina 27710
| | - Lisa St John-Williams
- ‡‡Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, Medical Center, Durham, North Carolina 27710
| | - M Arthur Moseley
- ‡‡Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, Medical Center, Durham, North Carolina 27710
| | - Rachael L Hardison
- From the ‡The Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio 43205
| | - Derek R Heimlich
- From the ‡The Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio 43205
| | | | - Joseph E Kerschner
- ‖Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin 53226; **Division of Pediatric Otolaryngology, Children's Hospital of Wisconsin, Milwaukee, Wisconsin 53226
| | - Sheryl S Justice
- From the ‡The Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio 43205; §The Center for Microbial Interface Biology and Department of Pediatrics, The Ohio State University, Columbus, Ohio 43210
| | - J Will Thompson
- ‡‡Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, Medical Center, Durham, North Carolina 27710
| | - Kevin M Mason
- From the ‡The Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio 43205; §The Center for Microbial Interface Biology and Department of Pediatrics, The Ohio State University, Columbus, Ohio 43210;
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The Stationary-Phase Cells of Saccharomyces cerevisiae Display Dynamic Actin Filaments Required for Processes Extending Chronological Life Span. Mol Cell Biol 2015; 35:3892-908. [PMID: 26351139 DOI: 10.1128/mcb.00811-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 08/31/2015] [Indexed: 11/20/2022] Open
Abstract
Stationary-growth-phase Saccharomyces cerevisiae yeast cultures consist of nondividing cells that undergo chronological aging. For their successful survival, the turnover of proteins and organelles, ensured by autophagy and the activation of mitochondria, is performed. Some of these processes are engaged in by the actin cytoskeleton. In S. cerevisiae stationary-phase cells, F actin has been shown to form static aggregates named actin bodies, subsequently cited to be markers of quiescence. Our in vivo analyses revealed that stationary-phase cultures contain cells with dynamic actin filaments, besides the cells with static actin bodies. The cells with dynamic actin displayed active endocytosis and autophagy and well-developed mitochondrial networks. Even more, stationary-phase cell cultures grown under calorie restriction predominantly contained cells with actin cables, confirming that the presence of actin cables is linked to successful adaptation to stationary phase. Cells with actin bodies were inactive in endocytosis and autophagy and displayed aberrations in mitochondrial networks. Notably, cells of the respiratory activity-deficient cox4Δ strain displayed the same mitochondrial aberrations and actin bodies only. Additionally, our results indicate that mitochondrial dysfunction precedes the formation of actin bodies and the appearance of actin bodies corresponds to decreased cell fitness. We conclude that the F-actin status reflects the extent of damage that arises from exponential growth.
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Moreau K, Ghislat G, Hochfeld W, Renna M, Zavodszky E, Runwal G, Puri C, Lee S, Siddiqi F, Menzies FM, Ravikumar B, Rubinsztein DC. Transcriptional regulation of Annexin A2 promotes starvation-induced autophagy. Nat Commun 2015; 6:8045. [PMID: 26289944 PMCID: PMC4560779 DOI: 10.1038/ncomms9045] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 07/11/2015] [Indexed: 01/05/2023] Open
Abstract
Autophagy is an important degradation pathway, which is induced after starvation, where it buffers nutrient deprivation by recycling macromolecules in organisms from yeast to man. While the classical pathway mediating this response is via mTOR inhibition, there are likely to be additional pathways that support the process. Here, we identify Annexin A2 as an autophagy modulator that regulates autophagosome formation by enabling appropriate ATG9A trafficking from endosomes to autophagosomes via actin. This process is dependent on the Annexin A2 effectors ARP2 and Spire1. Annexin A2 expression increases after starvation in cells in an mTOR-independent fashion. This is mediated via Jun N-terminal kinase activation of c-Jun, which, in turn, enhances the trans-activation of the Annexin A2 promoter. Annexin A2 knockdown abrogates starvation-induced autophagy, while its overexpression induces autophagy. Hence, c-Jun-mediated transcriptional responses support starvation-induced autophagy by regulating Annexin A2 expression levels.
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Affiliation(s)
- Kevin Moreau
- Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - Ghita Ghislat
- Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - Warren Hochfeld
- Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - Maurizio Renna
- Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - Eszter Zavodszky
- Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - Gautam Runwal
- Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - Claudia Puri
- Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - Shirley Lee
- Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - Farah Siddiqi
- Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - Fiona M. Menzies
- Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - Brinda Ravikumar
- Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - David C. Rubinsztein
- Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
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Mi N, Chen Y, Wang S, Chen M, Zhao M, Yang G, Ma M, Su Q, Luo S, Shi J, Xu J, Guo Q, Gao N, Sun Y, Chen Z, Yu L. CapZ regulates autophagosomal membrane shaping by promoting actin assembly inside the isolation membrane. Nat Cell Biol 2015; 17:1112-23. [DOI: 10.1038/ncb3215] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Accepted: 07/01/2015] [Indexed: 12/16/2022]
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Cemma M, Lam GY, Stöckli M, Higgins DE, Brumell JH. Strain-Specific Interactions of Listeria monocytogenes with the Autophagy System in Host Cells. PLoS One 2015; 10:e0125856. [PMID: 25970638 PMCID: PMC4430529 DOI: 10.1371/journal.pone.0125856] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 03/26/2015] [Indexed: 12/22/2022] Open
Abstract
Listeria monocytogenes is an intracellular bacterial pathogen that can replicate in the cytosol of host cells. These bacteria undergo actin-based motility in the cytosol via expression of ActA, which recruits host actin-regulatory proteins to the bacterial surface. L. monocytogenes is thought to evade killing by autophagy using ActA-dependent mechanisms. ActA-independent mechanisms of autophagy evasion have also been proposed, but remain poorly understood. Here we examined autophagy of non-motile (ΔactA) mutants of L. monocytogenes strains 10403S and EGD-e, two commonly studied strains of this pathogen. The ΔactA mutants displayed accumulation of ubiquitinated proteins and p62/SQSTM1 on their surface. However, only strain EGD-e ΔactA displayed colocalization with the autophagy marker LC3 at 8 hours post infection. A bacteriostatic agent (chloramphenicol) was required for LC3 recruitment to 10403S ΔactA, suggesting that these bacteria produce a factor for autophagy evasion. Internalin K was proposed to block autophagy of L. monocytogenes in the cytosol of host cells. However, deletion of inlK in either the wild-type or ΔactA background of strain 10403S had no impact on autophagy evasion by bacteria, indicating it does not play an essential role in evading autophagy. Replication of ΔactA mutants of strain EGD-e and 10403S was comparable to their parent wild-type strain in macrophages. Thus, ΔactA mutants of L. monocytogenes can block killing by autophagy at a step downstream of protein ubiquitination and, in the case of strain EGD-e, downstream of LC3 recruitment to bacteria. Our findings highlight the strain-specific differences in the mechanisms that L. monocytogenes uses to evade killing by autophagy in host cells.
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Affiliation(s)
- Marija Cemma
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Grace Y. Lam
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Martina Stöckli
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115, United States of America
| | - Darren E. Higgins
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115, United States of America
| | - John H. Brumell
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A8, Canada
- * E-mail:
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Backues SK, Orban DP, Bernard A, Singh K, Cao Y, Klionsky DJ. Atg23 and Atg27 act at the early stages of Atg9 trafficking in S. cerevisiae. Traffic 2014; 16:172-90. [PMID: 25385507 DOI: 10.1111/tra.12240] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 11/07/2014] [Accepted: 11/07/2014] [Indexed: 01/11/2023]
Abstract
Atg9 is a conserved multipass transmembrane protein with an essential role in autophagy. In Saccharomyces cerevisiae, it travels through the secretory pathway to a unique compartment, the Atg9 peripheral structures. These structures are then targeted to the phagophore assembly site (PAS), where they are proposed to help deliver membrane to the forming autophagosome. We used 'in vivo reconstitution' of this process in a multiple-knockout strain to define four proteins, Atg11, Atg19, Atg23 and Atg27, as the core minimal machinery necessary and sufficient for the trafficking of Atg9 to the PAS. Atg23 and Atg27 function in the formation of the Atg9 peripheral structures. Overexpression of Atg9 can bypass the need for Atg23, suggesting that the amount of Atg9 in each peripheral structure is a critical factor in their targeting to the PAS. In contrast, overexpression of Atg23 or Atg27 interferes with Atg9 trafficking, suggesting that these proteins must be present in the appropriate stoichiometry in order to function properly. These data allow us to resolve existing controversies regarding the role of Atg23 and Atg27, and propose a model that ties together previous observations regarding the role of Atg9 in autophagosome formation.
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Affiliation(s)
- Steven K Backues
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA; Current address: Department of Chemistry, Eastern Michigan University, Ypsilanti, MI, USA
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Xiao X, Mruk DD, Tang EI, Massarwa R, Mok KW, Li N, Wong CKC, Lee WM, Snapper SB, Shilo BZ, Schejter ED, Cheng CY. N-wasp is required for structural integrity of the blood-testis barrier. PLoS Genet 2014; 10:e1004447. [PMID: 24967734 PMCID: PMC4072540 DOI: 10.1371/journal.pgen.1004447] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 05/02/2014] [Indexed: 01/06/2023] Open
Abstract
During spermatogenesis, the blood-testis barrier (BTB) segregates the adluminal (apical) and basal compartments in the seminiferous epithelium, thereby creating a privileged adluminal environment that allows post-meiotic spermatid development to proceed without interference of the host immune system. A key feature of the BTB is its continuous remodeling within the Sertoli cells, the major somatic component of the seminiferous epithelium. This remodeling is necessary to allow the transport of germ cells towards the seminiferous tubule interior, while maintaining intact barrier properties. Here we demonstrate that the actin nucleation promoting factor Neuronal Wiskott-Aldrich Syndrome Protein (N-WASP) provides an essential function necessary for BTB restructuring, and for maintaining spermatogenesis. Our data suggests that the N-WASP-Arp2/3 actin polymerization machinery generates branched-actin arrays at an advanced stage of BTB remodeling. These arrays are proposed to mediate the restructuring process through endocytic recycling of BTB components. Disruption of N-WASP in Sertoli cells results in major structural abnormalities to the BTB, including mis-localization of critical junctional and cytoskeletal elements, and leads to disruption of barrier function. These impairments result in a complete arrest of spermatogenesis, underscoring the critical involvement of the somatic compartment of the seminiferous tubules in germ cell maturation. Mammalian spermatogenesis takes place within a sheltered environment, whereby somatic Sertoli cells protect and guide germ cells as they mature and differentiate. A key structure generated by the protective Sertoli cell epithelium is the blood-testis barrier (BTB), a composite of junctional and cytoskeletal elements, which prevents exposure of post-meiotic spermatids to the immune system. The BTB is a highly dynamic structure, which needs to be dismantled and rapidly rebuilt, in order to allow passage of maturing preleptotene spermatocytes, without compromising their isolation. Here we show that N-WASP, a conserved facilitator of formation of branched actin microfilament arrays, provides a function that is essential for maintenance of an intact BTB. Genetic disruption of N-WASP in mouse Sertoli cells leads to loss of BTB impermeability, resulting in a complete arrest of spermatogenesis at early and post-meiotic stages. Based on the localization patterns of key elements, we propose that branched-actin filaments participate in recycling of BTB materials to ensure the dynamic and efficient maintenance of this structure, one of a series of blood-tissue barriers that preserve privileged organ environments.
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Affiliation(s)
- Xiang Xiao
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Dolores D. Mruk
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Elizabeth I. Tang
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - R'ada Massarwa
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Ka Wai Mok
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Nan Li
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Chris K. C. Wong
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Will M. Lee
- School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - Scott B. Snapper
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ben-Zion Shilo
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Eyal D. Schejter
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
- * E-mail: (EDS); (CYC)
| | - C. Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York, United States of America
- * E-mail: (EDS); (CYC)
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Zientara-Rytter K, Sirko A. Selective autophagy receptor Joka2 co-localizes with cytoskeleton in plant cells. PLANT SIGNALING & BEHAVIOR 2014; 9:e28523. [PMID: 24705105 PMCID: PMC4091515 DOI: 10.4161/psb.28523] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 03/12/2014] [Accepted: 03/12/2014] [Indexed: 05/08/2023]
Abstract
Autophagy, especially selective autophagy, is poorly characterized in plants compared with mammals and yeasts, where numerous factors required for the proper regulation of autophagy have been identified. The evidence for the importance of the cytoskeleton (both actin filaments and microtubules) in various aspects of autophagy comes mostly from work on yeasts and mammals, while in plant cells these links are poorly explored. In this report we demonstrate that tobacco protein Joka2, a member of a family of selective autophagy cargo receptors closely related to mammalian NBR1 and p62 colocalizes with both major cytoskeletal components, microtubules and microfilaments and, additionally, resides in close proximity of the ER.
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Affiliation(s)
| | - Agnieszka Sirko
- Institute of Biochemistry and Biophysics; Polish Academy of Sciences; Warsaw, Poland
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Abstract
Autophagy refers to a group of processes that involve degradation of cytoplasmic components including cytosol, macromolecular complexes, and organelles, within the vacuole or the lysosome of higher eukaryotes. The various types of autophagy have attracted increasing attention for at least two reasons. First, autophagy provides a compelling example of dynamic rearrangements of subcellular membranes involving issues of protein trafficking and organelle identity, and thus it is fascinating for researchers interested in questions pertinent to basic cell biology. Second, autophagy plays a central role in normal development and cell homeostasis, and, as a result, autophagic dysfunctions are associated with a range of illnesses including cancer, diabetes, myopathies, some types of neurodegeneration, and liver and heart diseases. That said, this review focuses on autophagy in yeast. Many aspects of autophagy are conserved from yeast to human; in particular, this applies to the gene products mediating these pathways as well as some of the signaling cascades regulating it, so that the information we relate is relevant to higher eukaryotes. Indeed, as with many cellular pathways, the initial molecular insights were made possible due to genetic studies in Saccharomyces cerevisiae and other fungi.
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Matsumura F, Yamakita Y, Starovoytov V, Yamashiro S. Fascin confers resistance to Listeria infection in dendritic cells. THE JOURNAL OF IMMUNOLOGY 2013; 191:6156-64. [PMID: 24244012 DOI: 10.4049/jimmunol.1300498] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Ag-presenting dendritic cells (DCs) must survive bacterial infection to present Ag information to naive T cells. The greater ability of DCs' host defense is evident from the report that DCs are more resistant to Listeria monocytogenes than macrophages. However, the molecular mechanism of this resistance is unclear. We found that Listeria replicate more slowly in wild-type DCs compared with fascin1 knockout DCs. This finding is significant because fascin1, an actin-bundling protein, is specifically and greatly induced upon maturation of dendritic cells, but not other blood cells, including macrophages and neutrophils. Infection by Listeria makes phagosomes more acidic in wild-type DCs than in fascin1 knockout DCs, suggesting that fascin1 facilitates phagolysosomal fusion for killing of phagocytosed Listeria. We further found that fascin1 binds to LC3, an autophagosome marker, both in vivo and in vitro. Listeria are associated with LC3 to a greater extent in wild-type DCs than in fascin1 knockout DCs, suggesting that fascin1 facilitates autophagy for eradication of cytoplasmic Listeria. Taken together, our results suggest that fascin1 plays critical roles in the survival of DCs during Listeria infection, allowing DCs to function in innate and adaptive immunity.
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Affiliation(s)
- Fumio Matsumura
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854
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Mesa-Pereira B, Medina C, Camacho EM, Flores A, Santero E. Novel tools to analyze the function of Salmonella effectors show that SvpB ectopic expression induces cell cycle arrest in tumor cells. PLoS One 2013; 8:e78458. [PMID: 24205236 PMCID: PMC3804527 DOI: 10.1371/journal.pone.0078458] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 09/12/2013] [Indexed: 01/26/2023] Open
Abstract
In order to further characterize its role in pathogenesis and to establish whether its overproduction can lead to eukaryotic tumor cell death, Salmonella strains able to express its virulence factor SpvB (an ADP-ribosyl transferase enzyme) in a salicylate-inducible way have been constructed and analyzed in different eukaryotic tumor cell lines. To do so, the bacterial strains bearing the expression system have been constructed in a ∆purD background, which allows control of bacterial proliferation inside the eukaryotic cell. In the absence of bacterial proliferation, salicylate-induced SpvB production resulted in activation of caspases 3 and 7 and apoptotic cell death. The results clearly indicated that controlled SpvB production leads to F-actin depolimerization and either G1/S or G2/M phase arrest in all cell lines tested, thus shedding light on the function of SpvB in Salmonella pathogenesis. In the first place, the combined control of protein production by salicylate regulated vectors and bacterial growth by adenine concentration offers the possibility to study the role of Salmonella effectors during eukaryotic cells infection. In the second place, the salicylate-controlled expression of SpvB by the bacterium provides a way to evaluate the potential of other homologous or heterologous proteins as antitumor agents, and, eventually to construct novel potential tools for cancer therapy, given that Salmonella preferentially proliferates in tumors.
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Affiliation(s)
- Beatriz Mesa-Pereira
- Centro Andaluz de Biología del Desarrollo/ CSIC/ Universidad Pablo de Olavide/ Junta de Andalucía. Departamento de Biología Molecular e Ingeniería Bioquímica, Seville, Spain
| | - Carlos Medina
- Centro Andaluz de Biología del Desarrollo/ CSIC/ Universidad Pablo de Olavide/ Junta de Andalucía. Departamento de Biología Molecular e Ingeniería Bioquímica, Seville, Spain
| | - Eva María Camacho
- Centro Andaluz de Biología del Desarrollo/ CSIC/ Universidad Pablo de Olavide/ Junta de Andalucía. Departamento de Biología Molecular e Ingeniería Bioquímica, Seville, Spain
| | - Amando Flores
- Centro Andaluz de Biología del Desarrollo/ CSIC/ Universidad Pablo de Olavide/ Junta de Andalucía. Departamento de Biología Molecular e Ingeniería Bioquímica, Seville, Spain
- * E-mail:
| | - Eduardo Santero
- Centro Andaluz de Biología del Desarrollo/ CSIC/ Universidad Pablo de Olavide/ Junta de Andalucía. Departamento de Biología Molecular e Ingeniería Bioquímica, Seville, Spain
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Wang K, Jin M, Liu X, Klionsky DJ. Proteolytic processing of Atg32 by the mitochondrial i-AAA protease Yme1 regulates mitophagy. Autophagy 2013; 9:1828-36. [PMID: 24025448 DOI: 10.4161/auto.26281] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mitophagy, the autophagic removal of mitochondria, occurs through a highly selective mechanism. In the yeast Saccharomyces cerevisiae, the mitochondrial outer membrane protein Atg32 confers selectivity for mitochondria sequestration as a cargo by the autophagic machinery through its interaction with Atg11, a scaffold protein for selective types of autophagy. The activity of mitophagy in vivo must be tightly regulated considering that mitochondria are essential organelles that produce most of the cellular energy, but also generate reactive oxygen species that can be harmful to cell physiology. We found that Atg32 was proteolytically processed at its C terminus upon mitophagy induction. Adding an epitope tag to the C terminus of Atg32 interfered with its processing and caused a mitophagy defect, suggesting the processing is required for efficient mitophagy. Furthermore, we determined that the mitochondrial i-AAA protease Yme1 mediated Atg32 processing and was required for mitophagy. Finally, we found that the interaction between Atg32 and Atg11 was significantly weakened in yme1∆ cells. We propose that the processing of Atg32 by Yme1 acts as an important regulatory mechanism of cellular mitophagy activity.
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Affiliation(s)
- Ke Wang
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology; University of Michigan; Ann Arbor, MI USA
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Bánréti A, Sass M, Graba Y. The emerging role of acetylation in the regulation of autophagy. Autophagy 2013; 9:819-29. [PMID: 23466676 DOI: 10.4161/auto.23908] [Citation(s) in RCA: 149] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Autophagy is an evolutionarily conserved catabolic process through which different components of the cells are sequestered into double-membrane cytosolic vesicles called autophagosomes, and fated to degradation through fusion with lysosomes. Autophagy plays a major function in many physiological processes including response to different stress factors, energy homeostasis, elimination of cellular organelles and tissue remodeling during development. Consequently, autophagy is strictly controlled and post-translational modifications such as phosphorylation and ubiquitination have long been associated with autophagy regulation. In contrast, the importance of acetylation in autophagy control has only emerged in the last few years. In this review, we summarize how previously identified histone acetylases and deacetylases modify key autophagic effector proteins, and discuss how this has an impact on physiological and pathological cellular processes.
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Affiliation(s)
- Agnes Bánréti
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, Hungary.
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