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Yu J, Zhou J. Vacuolar accumulation and colocalization is not a proper criterion for cytoplasmic soluble proteins undergoing selective autophagy. Plant Signal Behav 2021; 16:1932319. [PMID: 34176421 PMCID: PMC8331019 DOI: 10.1080/15592324.2021.1932319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Autophagy is an important cytoprotective process that mediates degradation of dysfunctional or unnecessary cellular components. In the process of autophagy, a double-membrane organelle termed the autophagosome is formed to sequestrate portions of cytoplasm and subsequently delivered into lysosome or vacuole for degradation. The accumulation of autophagic bodies in the vacuoles after treatment with concanamycin A (ConcA) is a widely used protocol for monitoring the occurrence of autophagy in plants. Here, it was found that the cytoplasmic soluble GFP was accumulated in vacuoles upon ConcA treatment. Importantly, the GFP signal showed good colocalization with the autophagic marker mCherry-ATG8f in vacuoles based on two commonly used methods, the Pearson-Spearman correlation colocalization analysis and the plot profile analysis. Further results showed that the free GFP did not interact with ATG8s. Thus, analysis of accumulation and colocalization only in vacuoles is not a trustworthy way to judge whether degradation of cytoplasmic protein is dependent on the selective autophagy pathway in plants. In this short perspective, we propose several primary steps to distinguish that the cytoplasmic proteins are degraded by selective or bulk autophagy, hoping they could contribute to identify and clarify the selective autophagic cargos and receptors in plants.
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Affiliation(s)
- Jingfang Yu
- MOE Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, China
| | - Jun Zhou
- MOE Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, China
- Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, College of Biophotonics, South China Normal University, Guangzhou, China
- CONTACT Jun Zhou Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, Rm 610, College of Biophotonics, South China Normal University, Guangzhou510631, CHINA
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Watanabe A, Togi M, Koya T, Taniguchi M, Sakamoto T, Iwabuchi K, Kato T, Shimodaira S. Identification of CD56 dim subpopulation marked with high expression of GZMB/PRF1/PI-9 in CD56 + interferon-α-induced dendritic cells. Genes Cells 2021; 26:313-327. [PMID: 33662167 DOI: 10.1111/gtc.12844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 02/15/2021] [Accepted: 02/28/2021] [Indexed: 01/08/2023]
Abstract
As the sentinels of innate and adaptive immune system, dendritic cells (DCs) have been considered to hold a great promise for medical application. Among the diverse types of DCs, monocyte-derived DCs (mo-DCs) generated in vitro have been most commonly employed. We have been improving the culture protocol and devised a protocol to produce mature interferon-α-induced DCs (IFN-DCs), hereinafter called (mat)IFN-DCs. While exploring the relationship between the expression of CD56 and the cytotoxic activity of (mat)IFN-DCs, we unexpectedly found that sorting of (mat)IFN-DCs with CD56 antibody-coated microbeads (MB) resulted in fractionating cells with tumoricidal activity into the flow-through (FT) but not MB-bound fraction. We uncovered that the FT fraction contains cells expressing low but substantial level of CD56. Moreover, those cells express granzyme B (GrB), perforin (PFN), and serpin B9 at high levels. By employing a specific inhibitor of PFN, we confirmed that direct tumoricidal activity relies on the GrB/PFN pathway. We designated subpopulation in FT fraction as CD56dim and that in CD56 positively sorted fraction as CD56bright , respectively. This is the first time, to our knowledge, to identify subpopulations of CD56-positive IFN-DCs with distinct tumoricidal activity which is ascribed to high expression of the components of GrB/PFN pathway.
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Affiliation(s)
- Asuka Watanabe
- Department of Regenerative Medicine, School of Medicine, Kanazawa Medical University, Kahoku-gun, Japan
| | - Misa Togi
- Department of Regenerative Medicine, School of Medicine, Kanazawa Medical University, Kahoku-gun, Japan.,Division of Stem Cell Medicine, Department of Advanced Medicine, Medical Research Institute, Kanazawa Medical University, Kahoku-gun, Japan
| | - Terutsugu Koya
- Department of Regenerative Medicine, School of Medicine, Kanazawa Medical University, Kahoku-gun, Japan
| | - Makoto Taniguchi
- Division of Genome Damage Response Research, Department of Life Science, Medical Research Institute, Kanazawa Medical University, Kahoku-gun, Japan
| | - Takuya Sakamoto
- Department of Regenerative Medicine, School of Medicine, Kanazawa Medical University, Kahoku-gun, Japan
| | - Kuniyoshi Iwabuchi
- Division of Genome Damage Response Research, Department of Life Science, Medical Research Institute, Kanazawa Medical University, Kahoku-gun, Japan.,Department of Biochemistry I, School of Medicine, Kanazawa Medical University, Kahoku-gun, Japan
| | - Tomohisa Kato
- Division of Stem Cell Medicine, Department of Advanced Medicine, Medical Research Institute, Kanazawa Medical University, Kahoku-gun, Japan
| | - Shigetaka Shimodaira
- Department of Regenerative Medicine, School of Medicine, Kanazawa Medical University, Kahoku-gun, Japan.,Division of Stem Cell Medicine, Department of Advanced Medicine, Medical Research Institute, Kanazawa Medical University, Kahoku-gun, Japan
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Acheampong AK, Shanks C, Cheng CY, Schaller GE, Dagdas Y, Kieber JJ. EXO70D isoforms mediate selective autophagic degradation of type-A ARR proteins to regulate cytokinin sensitivity. Proc Natl Acad Sci U S A 2020; 117:27034-27043. [PMID: 33051300 PMCID: PMC7604425 DOI: 10.1073/pnas.2013161117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The phytohormone cytokinin influences many aspects of plant growth and development, several of which also involve the cellular process of autophagy, including leaf senescence, nutrient remobilization, and developmental transitions. The Arabidopsis type-A response regulators (type-A ARR) are negative regulators of cytokinin signaling that are transcriptionally induced in response to cytokinin. Here, we describe a mechanistic link between cytokinin signaling and autophagy, demonstrating that plants modulate cytokinin sensitivity through autophagic regulation of type-A ARR proteins. Type-A ARR proteins were degraded by autophagy in an AUTOPHAGY-RELATED (ATG)5-dependent manner, and this degradation is promoted by phosphorylation on a conserved aspartate in the receiver domain of the type-A ARRs. EXO70D family members interacted with type-A ARR proteins, likely in a phosphorylation-dependent manner, and recruited them to autophagosomes via interaction of the EXO70D AIM with the core autophagy protein, ATG8. Consistently, loss-of-function exo70D1,2,3 mutants exhibited compromised targeting of type-A ARRs to autophagic vesicles, have elevated levels of type-A ARR proteins, and are hyposensitive to cytokinin. Disruption of both type-A ARRs and EXO70D1,2,3 compromised survival in carbon-deficient conditions, suggesting interaction between autophagy and cytokinin responsiveness in response to stress. These results indicate that the EXO70D proteins act as selective autophagy receptors to target type-A ARR cargos for autophagic degradation, demonstrating modulation of cytokinin signaling by selective autophagy.
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Affiliation(s)
| | - Carly Shanks
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Chia-Yi Cheng
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - G Eric Schaller
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | - Yasin Dagdas
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Joseph J Kieber
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599;
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Painter MM, Zimmerman GE, Merlino MS, Robertson AW, Terry VH, Ren X, McLeod MR, Gomez-Rodriguez L, Garcia KA, Leonard JA, Leopold KE, Neevel AJ, Lubow J, Olson E, Piechocka-Trocha A, Collins DR, Tripathi A, Raghavan M, Walker BD, Hurley JH, Sherman DH, Collins KL. Concanamycin A counteracts HIV-1 Nef to enhance immune clearance of infected primary cells by cytotoxic T lymphocytes. Proc Natl Acad Sci U S A 2020; 117:23835-23846. [PMID: 32900948 PMCID: PMC7519347 DOI: 10.1073/pnas.2008615117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Nef is an HIV-encoded accessory protein that enhances pathogenicity by down-regulating major histocompatibility class I (MHC-I) expression to evade killing by cytotoxic T lymphocytes (CTLs). A potent Nef inhibitor that restores MHC-I is needed to promote immune-mediated clearance of HIV-infected cells. We discovered that the plecomacrolide family of natural products restored MHC-I to the surface of Nef-expressing primary cells with variable potency. Concanamycin A (CMA) counteracted Nef at subnanomolar concentrations that did not interfere with lysosomal acidification or degradation and were nontoxic in primary cell cultures. CMA specifically reversed Nef-mediated down-regulation of MHC-I, but not CD4, and cells treated with CMA showed reduced formation of the Nef:MHC-I:AP-1 complex required for MHC-I down-regulation. CMA restored expression of diverse allotypes of MHC-I in Nef-expressing cells and inhibited Nef alleles from divergent clades of HIV and simian immunodeficiency virus, including from primary patient isolates. Lastly, we found that restoration of MHC-I in HIV-infected cells was accompanied by enhanced CTL-mediated clearance of infected cells comparable to genetic deletion of Nef. Thus, we propose CMA as a lead compound for therapeutic inhibition of Nef to enhance immune-mediated clearance of HIV-infected cells.
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Affiliation(s)
- Mark M Painter
- Graduate Program in Immunology, University of Michigan, Ann Arbor, MI 48109
| | | | - Madeline S Merlino
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Andrew W Robertson
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
- Natural Products Discovery Core, Life Sciences Institute, University of Michigan Ann Arbor, MI 48109
| | - Valeri H Terry
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Xuefeng Ren
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720
| | - Megan R McLeod
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Lyanne Gomez-Rodriguez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
- Graduate Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109
| | - Kirsten A Garcia
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Jolie A Leonard
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Kay E Leopold
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Andrew J Neevel
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Jay Lubow
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109
| | - Eli Olson
- Graduate Program in Immunology, University of Michigan, Ann Arbor, MI 48109
| | - Alicja Piechocka-Trocha
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
| | - David R Collins
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
| | - Ashootosh Tripathi
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
- Natural Products Discovery Core, Life Sciences Institute, University of Michigan Ann Arbor, MI 48109
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Malini Raghavan
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109
| | - Bruce D Walker
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
| | - James H Hurley
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720
| | - David H Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Kathleen L Collins
- Graduate Program in Immunology, University of Michigan, Ann Arbor, MI 48109;
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI 48109
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Atakpa P, Thillaiappan NB, Mataragka S, Prole DL, Taylor CW. IP 3 Receptors Preferentially Associate with ER-Lysosome Contact Sites and Selectively Deliver Ca 2+ to Lysosomes. Cell Rep 2019; 25:3180-3193.e7. [PMID: 30540949 PMCID: PMC6302550 DOI: 10.1016/j.celrep.2018.11.064] [Citation(s) in RCA: 113] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 07/30/2018] [Accepted: 11/15/2018] [Indexed: 12/22/2022] Open
Abstract
Inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs) allow extracellular stimuli to redistribute Ca2+ from the ER to cytosol or other organelles. We show, using small interfering RNA (siRNA) and vacuolar H+-ATPase (V-ATPase) inhibitors, that lysosomes sequester Ca2+ released by all IP3R subtypes, but not Ca2+ entering cells through store-operated Ca2+ entry (SOCE). A low-affinity Ca2+ sensor targeted to lysosomal membranes reports large, local increases in cytosolic [Ca2+] during IP3-evoked Ca2+ release, but not during SOCE. Most lysosomes associate with endoplasmic reticulum (ER) and dwell at regions populated by IP3R clusters, but IP3Rs do not assemble ER-lysosome contacts. Increasing lysosomal pH does not immediately prevent Ca2+ uptake, but it causes lysosomes to slowly redistribute and enlarge, reduces their association with IP3Rs, and disrupts Ca2+ exchange with ER. In a "piston-like" fashion, ER concentrates cytosolic Ca2+ and delivers it, through large-conductance IP3Rs, to a low-affinity lysosomal uptake system. The involvement of IP3Rs allows extracellular stimuli to regulate Ca2+ exchange between the ER and lysosomes.
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Affiliation(s)
- Peace Atakpa
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | | | - Stefania Mataragka
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - David L Prole
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Colin W Taylor
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK.
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Zhou A, Bu Y, Takano T, Zhang X, Liu S. Conserved V-ATPase c subunit plays a role in plant growth by influencing V-ATPase-dependent endosomal trafficking. Plant Biotechnol J 2016; 14:271-283. [PMID: 25917395 DOI: 10.1111/pbi.12381] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 03/10/2015] [Accepted: 03/18/2015] [Indexed: 06/04/2023]
Abstract
In plant cells, the vacuolar-type H(+)-ATPases (V-ATPase) are localized in the tonoplast, Golgi, trans-Golgi network and endosome. However, little is known about how V-ATPase influences plant growth, particularly with regard to the V-ATPase c subunit (VHA-c). Here, we characterized the function of a VHA-c gene from Puccinellia tenuiflora (PutVHA-c) in plant growth. Compared to the wild-type, transgenic plants overexpressing PutVHA-c in Arabidopsis thaliana exhibit better growth phenotypes in root length, fresh weight, plant height and silique number under the normal and salt stress conditions due to noticeably higher V-ATPase activity. Consistently, the Arabidopsis atvha-c5 mutant shows reduced V-ATPase activity and retarded plant growth. Furthermore, confocal and immunogold electron microscopy assays demonstrate that PutVHA-c is mainly localized to endosomal compartments. The treatment of concanamycin A (ConcA), a specific inhibitor of V-ATPases, leads to obvious aggregation of the endosomal compartments labelled with PutVHA-c-GFP. Moreover, ConcA treatment results in the abnormal localization of two plasma membrane (PM) marker proteins Pinformed 1 (AtPIN1) and regulator of G protein signalling-1 (AtRGS1). These findings suggest that the decrease in V-ATPase activity blocks endosomal trafficking. Taken together, our results strongly suggest that the PutVHA-c plays an important role in plant growth by influencing V-ATPase-dependent endosomal trafficking.
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Affiliation(s)
- Aimin Zhou
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration in Oil Field (SAVER), Ministry of Education, Alkali Soil Natural Environmental Science Center (ASNESC), Northeast Forestry University, Harbin, China
| | - Yuanyuan Bu
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration in Oil Field (SAVER), Ministry of Education, Alkali Soil Natural Environmental Science Center (ASNESC), Northeast Forestry University, Harbin, China
| | - Tetsuo Takano
- Asian Natural Environmental Science Center, The University of Tokyo, Nishitokyo-shi, Tokyo, Japan
| | - Xinxin Zhang
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration in Oil Field (SAVER), Ministry of Education, Alkali Soil Natural Environmental Science Center (ASNESC), Northeast Forestry University, Harbin, China
| | - Shenkui Liu
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration in Oil Field (SAVER), Ministry of Education, Alkali Soil Natural Environmental Science Center (ASNESC), Northeast Forestry University, Harbin, China
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