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Wang QQ, Sun M, Tang T, Lai DH, Liu J, Maity S, He K, Wu XT, Yang J, Li YB, Tang XY, Ding HY, Hide G, Distefano M, Lun ZR, Zhu XQ, Long S. Functional screening reveals Toxoplasma prenylated proteins required for endocytic trafficking and rhoptry protein sorting. mBio 2023; 14:e0130923. [PMID: 37548452 PMCID: PMC10470541 DOI: 10.1128/mbio.01309-23] [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: 05/24/2023] [Accepted: 06/12/2023] [Indexed: 08/08/2023] Open
Abstract
In the apicomplexans, endocytosed cargos (e.g., hemoglobin) are trafficked to a specialized organelle for digestion. This follows a unique endocytotic process at the micropore/cytostome in these parasites. However, the mechanism underlying endocytic trafficking remains elusive, due to the repurposing of classical endocytic proteins for the biogenesis of apical organelles. To resolve this issue, we have exploited the genetic tractability of the model apicomplexan Toxoplasma gondii, which ingests host cytosolic materials (e.g., green fluorescent protein[GFP]). We determined an association between protein prenylation and endocytic trafficking, and using an alkyne-labeled click chemistry approach, the prenylated proteome was characterized. Genome editing, using clustered regularly interspaced short palindromic repaet/CRISPR-associated nuclease 9 (CRISPR/Cas9), was efficiently utilized to generate genetically modified lines for the functional screening of 23 prenylated candidates. This identified four of these proteins that regulate the trafficking of endocytosed GFP vesicles. Among these proteins, Rab1B and YKT6.1 are highly conserved but are non-classical endocytic proteins in eukaryotes. Confocal imaging analysis showed that Rab1B and Ras are substantially localized to both the trans-Golgi network and the endosome-like compartments in the parasite. Conditional knockdown of Rab1B caused a rapid defect in secretory trafficking to the rhoptry bulb, suggesting a trafficking intersection role for the key regulator Rab1B. Further experiments confirmed a critical role for protein prenylation in regulating the stability/activity of these proteins (i.e., Rab1B and YKT6.1) in the parasite. Our findings define the molecular basis of endocytic trafficking and reveal a potential intersection function of Rab1B on membrane trafficking in T. gondii. This might extend to other related protists, including the malarial parasites. IMPORTANCE The protozoan Toxoplasma gondii establishes a permissive niche, in host cells, that allows parasites to acquire large molecules such as proteins. Numerous studies have demonstrated that the parasite repurposes the classical endocytic components for secretory sorting to the apical organelles, leaving the question of endocytic transport to the lysosome-like compartment unclear. Recent studies indicated that endocytic trafficking is likely to associate with protein prenylation in malarial parasites. This information promoted us to examine this association in the model apicomplexan T. gondii and to identify the key components of the prenylated proteome that are involved. By exploiting the genetic tractability of T. gondii and a host GFP acquisition assay, we reveal four non-classical endocytic proteins that regulate the transport of endocytosed cargos (e.g., GFP) in T. gondii. Thus, we extend the principle that protein prenylation regulates endocytic trafficking and elucidate the process of non-classical endocytosis in T. gondii and potentially in other related protists.
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Affiliation(s)
- Qiang-Qiang Wang
- National Key Laboratory of Veterinary Public Health Security and College of Veterinary Medicine, China Agricultural University, Beijing, China
- National Animal Protozoa Laboratory and School of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Ming Sun
- National Key Laboratory of Veterinary Public Health Security and College of Veterinary Medicine, China Agricultural University, Beijing, China
- National Animal Protozoa Laboratory and School of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Tao Tang
- National Key Laboratory of Veterinary Public Health Security and College of Veterinary Medicine, China Agricultural University, Beijing, China
- National Animal Protozoa Laboratory and School of Veterinary Medicine, China Agricultural University, Beijing, China
| | - De-Hua Lai
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jing Liu
- National Key Laboratory of Veterinary Public Health Security and College of Veterinary Medicine, China Agricultural University, Beijing, China
- National Animal Protozoa Laboratory and School of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Sanjay Maity
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Kai He
- National Key Laboratory of Veterinary Public Health Security and College of Veterinary Medicine, China Agricultural University, Beijing, China
- National Animal Protozoa Laboratory and School of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Xi-Ting Wu
- National Key Laboratory of Veterinary Public Health Security and College of Veterinary Medicine, China Agricultural University, Beijing, China
- National Animal Protozoa Laboratory and School of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Jiong Yang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yue-Bao Li
- National Key Laboratory of Veterinary Public Health Security and College of Veterinary Medicine, China Agricultural University, Beijing, China
- National Animal Protozoa Laboratory and School of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Xiao-Yan Tang
- National Key Laboratory of Veterinary Public Health Security and College of Veterinary Medicine, China Agricultural University, Beijing, China
- National Animal Protozoa Laboratory and School of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Hui-Yong Ding
- National Key Laboratory of Veterinary Public Health Security and College of Veterinary Medicine, China Agricultural University, Beijing, China
- National Animal Protozoa Laboratory and School of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Geoff Hide
- Biomedical Research and Innovation Centre and Environmental Research and Innovation Centre, School of Science, Engineering and Environment, University of Salford, Salford, United Kingdom
| | - Mark Distefano
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Zhao-Rong Lun
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Xing-Quan Zhu
- College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong, Shanxi Province, China
| | - Shaojun Long
- National Key Laboratory of Veterinary Public Health Security and College of Veterinary Medicine, China Agricultural University, Beijing, China
- National Animal Protozoa Laboratory and School of Veterinary Medicine, China Agricultural University, Beijing, China
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Ma T, Li E, Li LS, Li S, Zhang Y. The Arabidopsis R-SNARE protein YKT61 is essential for gametophyte development. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2021; 63:676-694. [PMID: 32918784 DOI: 10.1111/jipb.13017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 09/12/2020] [Indexed: 05/23/2023]
Abstract
Gametophyte development is a pre-requisite for plant reproduction and seed yield; therefore, studies of gametophyte development help us understand fundamental biological questions and have potential applications in agriculture. The biogenesis and dynamics of endomembrane compartments are critical for cell survival, and their regulatory mechanisms are just beginning to be revealed. Here, we report that the Arabidopsis thaliana SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) protein YKT61 is essential for both male and female gametogenesis. By using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9)-based genome editing, we demonstrated that male and female gametophytes carrying YKT61 loss-of-function alleles do not survive. Specifically, loss of YKT61 function resulted in the arrest of male gametophytic development at pollen mitosis I and the degeneration of female gametophytes. A three-base-pair deletion in YKT61 in the ykt61-3 mutant resulted in a single-amino acid deletion in the longin domain of YKT61; the resulting mutant protein does not interact with multiple SNAREs and showed substantially reduced membrane association, suggesting that the N-terminal longin domain of YKT61 plays multiple roles in its function. This study demonstrates that Arabidopsis YKT61 is essential for male and female gametogenesis and sets an example for functional characterization of essential genes with the combination of Cas9-mediated editing and expression from a Cas9-resistant transgene.
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Affiliation(s)
- Ting Ma
- State Key laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - En Li
- State Key laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Lu-Shen Li
- State Key laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Sha Li
- State Key laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Yan Zhang
- State Key laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
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Chen F, Amgalan D, Kitsis RN, Pessin JE, Feng D. ATG16L1 autophagy pathway regulates BAX protein levels and programmed cell death. J Biol Chem 2020; 295:15045-15053. [PMID: 32848017 PMCID: PMC7606669 DOI: 10.1074/jbc.ra120.013999] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 08/20/2020] [Indexed: 01/05/2023] Open
Abstract
Previously we reported that adipocyte SNAP23 (synaptosome-associated protein of 23 kDa) deficiency blocks the activation of macroautophagy, leading to an increased abundance of BAX, a pro-death Bcl-2 family member, and activation and adipocyte cell death both in vitro and in vivo Here, we found that knockdown of SNAP23 inhibited the association of the autophagosome regulators ATG16L1 and ATG9 compartments by nutrient depletion and reduced the formation of ATG16L1 membrane puncta. ATG16L1 knockdown inhibited autophagy flux and increased BAX protein levels by suppressing BAX degradation. The elevation in BAX protein had no effect on BAX activation or cell death in the nutrient-replete state. However, following nutrient depletion, BAX was activated with a concomitant induction of cell death. Co-immunoprecipitation analyses demonstrated that SNAP23 and ATG16L1 proteins form a stable complex independent of nutrient condition, whereas in the nutrient-depleted state, BAX binds to SNAP23 to form a ternary BAX-SNAP23-ATG16L1 protein complex. Taken together, these data support a model in which SNAP23 plays a crucial function as a scaffold for ATG16L1 necessary for the suppression of BAX activation and induction of the intrinsic cell death program.
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Affiliation(s)
- Fenfen Chen
- Fleischer Institute of Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Dulguun Amgalan
- Fleischer Institute of Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Richard N. Kitsis
- Fleischer Institute of Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, USA,Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, New York, USA,Wilf Family Cardiovascular Research Center, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Jeffrey E. Pessin
- Fleischer Institute of Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, USA,Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, New York, USA,Wilf Family Cardiovascular Research Center, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Daorong Feng
- Fleischer Institute of Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA,For correspondence: Daorong Feng,
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Wilkinson S. Emerging Principles of Selective ER Autophagy. J Mol Biol 2020; 432:185-205. [PMID: 31100386 PMCID: PMC6971691 DOI: 10.1016/j.jmb.2019.05.012] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/07/2019] [Accepted: 05/07/2019] [Indexed: 12/13/2022]
Abstract
The endoplasmic reticulum (ER) is a fundamental organelle in cellular metabolism and signal transduction. It is subject to complex, dynamic sculpting of morphology and composition. Degradation of ER content has an important role to play here. Indeed, a major emerging player in ER turnover is ER-phagy, the degradation of ER fragments by selective autophagy, particularly macroautophagy. This article proposes a number of unifying principles of ER-phagy mechanism and compares these with other selective autophagy pathways. A perspective on the likely roles of ER-phagy in determining cell fate is provided. Emerging related forms of intracellular catabolism of the ER or contents, including ER-phagy by microautophagy and selective ER protein removal via the lysosome, are outlined for comparison. Unresolved questions regarding the mechanism of ER-phagy and its significance in cellular and organismal health are put forward. This review concludes with a perspective on how this fundamental knowledge might inform future clinical developments.
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Affiliation(s)
- Simon Wilkinson
- Edinburgh Cancer Research UK Centre, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, EH4 2XR, United Kingdom
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5
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Abstract
Macroautophagy is an intracellular degradation system that delivers diverse cytoplasmic materials to lysosomes via autophagosomes. Recent advances have enabled identification of several selective autophagy substrates and receptors, greatly expanding our understanding of the cellular functions of autophagy. In this review, we describe the diverse cellular functions of macroautophagy, including its essential contribution to metabolic adaptation and cellular homeostasis. We also discuss emerging findings on the mechanisms and functions of various types of selective autophagy.
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Affiliation(s)
- Hideaki Morishita
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo 113-0033, Japan; ,
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo 113-0033, Japan; ,
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Kriegenburg F, Bas L, Gao J, Ungermann C, Kraft C. The multi-functional SNARE protein Ykt6 in autophagosomal fusion processes. Cell Cycle 2019; 18:639-651. [PMID: 30836834 PMCID: PMC6464585 DOI: 10.1080/15384101.2019.1580488] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 01/06/2019] [Accepted: 01/29/2019] [Indexed: 01/01/2023] Open
Abstract
Autophagy is a degradative pathway in which cytosolic material is enwrapped within double membrane vesicles, so-called autophagosomes, and delivered to lytic organelles. SNARE (Soluble N-ethylmaleimide sensitive factor attachment protein receptor) proteins are key to drive membrane fusion of the autophagosome and the lytic organelles, called lysosomes in higher eukaryotes or vacuoles in plants and yeast. Therefore, the identification of functional SNARE complexes is central for understanding fusion processes and their regulation. The SNARE proteins Syntaxin 17, SNAP29 and Vamp7/VAMP8 are responsible for the fusion of autophagosomes with lysosomes in higher eukaryotes. Recent studies reported that the R-SNARE Ykt6 is an additional SNARE protein involved in autophagosome-lytic organelle fusion in yeast, Drosophila, and mammals. These current findings point to an evolutionarily conserved role of Ykt6 in autophagosome-related fusion events. Here, we briefly summarize the principal mechanisms of autophagosome-lytic organelle fusion, with a special focus on Ykt6 to highlight some intrinsic features of this unusual SNARE protein.
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Affiliation(s)
- Franziska Kriegenburg
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Levent Bas
- Max F. Perutz Laboratories, Vienna Biocenter, University of Vienna, Vienna, Austria
| | - Jieqiong Gao
- Biochemistry Section, Department of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
| | - Christian Ungermann
- Biochemistry Section, Department of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
| | - Claudine Kraft
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Max F. Perutz Laboratories, Vienna Biocenter, University of Vienna, Vienna, Austria
- CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg
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