1
|
Laczkó-Dobos H, Bhattacharjee A, Maddali AK, Kincses A, Abuammar H, Sebők-Nagy K, Páli T, Dér A, Hegedűs T, Csordás G, Juhász G. PtdIns4P is required for the autophagosomal recruitment of STX17 (syntaxin 17) to promote lysosomal fusion. Autophagy 2024; 20:1639-1650. [PMID: 38411137 PMCID: PMC11210929 DOI: 10.1080/15548627.2024.2322493] [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: 08/31/2023] [Accepted: 02/20/2024] [Indexed: 02/28/2024] Open
Abstract
The autophagosomal SNARE STX17 (syntaxin 17) promotes lysosomal fusion and degradation, but its autophagosomal recruitment is incompletely understood. Notably, PtdIns4P is generated on autophagosomes and promotes fusion through an unknown mechanism. Here we show that soluble recombinant STX17 is spontaneously recruited to negatively charged liposomes and adding PtdIns4P to liposomes containing neutral lipids is sufficient for its recruitment. Consistently, STX17 colocalizes with PtdIns4P-positive autophagosomes in cells, and specific inhibition of PtdIns4P synthesis on autophagosomes prevents its loading. Molecular dynamics simulations indicate that C-terminal positively charged amino acids establish contact with membrane bilayers containing negatively charged PtdIns4P. Accordingly, Ala substitution of Lys and Arg residues in the C terminus of STX17 abolishes membrane binding and impairs its autophagosomal recruitment. Finally, only wild type but not Ala substituted STX17 expression rescues the autophagosome-lysosome fusion defect of STX17 loss-of-function cells. We thus identify a key step of autophagosome maturation that promotes lysosomal fusion.Abbreviations: Cardiolipin: 1',3'-bis[1-palmitoyl-2-oleoyl-sn-glycero-3-phospho]-glycerol; DMSO: dimethyl sulfoxide; GST: glutathione S-transferase; GUV: giant unilamellar vesicles; LAMP1: lysosomal associated membrane protein 1; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; PA: 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphate; PC/POPC: 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine; PG: 1-palmitoyl-2-linoleoyl-sn-glycero-3-phospho-(1'-rac-glycerol); PI: L-α-phosphatidylinositol; PI4K2A: phosphatidylinositol 4-kinase type 2 alpha; PIK3C3/VPS34: phosphatidylinositol 3-kinase catalytic subunit type 3; POPE/PE: 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine; PS: 1-stearoyl-2-linoleoyl-sn-glycero-3-phospho-L-serine; PtdIns(3,5)P2: 1,2-dioleoyl-sn-glycero-3-phospho-(1"-myo-inositol-3',5'-bisphosphate); PtdIns3P: 1,2- dioleoyl-sn-glycero-3-phospho-(1'-myo-inositol-3'-phosphate); PtdIns4P: 1,2-dioleoyl-sn-glycero-3-phospho-(1"-myo-inositol-4'-phosphate); SDS-PAGE: sodium dodecyl sulfate-polyacrylamide gel electrophoresis; STX17: syntaxin 17.
Collapse
Affiliation(s)
| | | | - Asha Kiran Maddali
- Institute of Genetics, HUN-REN Biological Research Centre Szeged, Szeged, Hungary
- Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - András Kincses
- Institute of Biophysics, HUN-REN Biological Research Centre Szeged, Szeged, Hungary
| | - Hussein Abuammar
- Institute of Genetics, HUN-REN Biological Research Centre Szeged, Szeged, Hungary
- Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - Krisztina Sebők-Nagy
- Institute of Biophysics, HUN-REN Biological Research Centre Szeged, Szeged, Hungary
| | - Tibor Páli
- Institute of Biophysics, HUN-REN Biological Research Centre Szeged, Szeged, Hungary
| | - András Dér
- Institute of Biophysics, HUN-REN Biological Research Centre Szeged, Szeged, Hungary
| | - Tamás Hegedűs
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
- HUN-REN Biophysical Virology Research Group, Budapest, Hungary
| | - Gábor Csordás
- Institute of Genetics, HUN-REN Biological Research Centre Szeged, Szeged, Hungary
| | - Gábor Juhász
- Institute of Genetics, HUN-REN Biological Research Centre Szeged, Szeged, Hungary
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, Hungary
| |
Collapse
|
2
|
Gkikas I, Daskalaki I, Kounakis K, Tavernarakis N, Lionaki E. MitoSNARE Assembly and Disassembly Factors Regulate Basal Autophagy and Aging in C. elegans. Int J Mol Sci 2023; 24:ijms24044230. [PMID: 36835643 PMCID: PMC9964399 DOI: 10.3390/ijms24044230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/30/2023] [Accepted: 02/14/2023] [Indexed: 02/23/2023] Open
Abstract
SNARE proteins reside between opposing membranes and facilitate vesicle fusion, a physiological process ubiquitously required for secretion, endocytosis and autophagy. With age, neurosecretory SNARE activity drops and is pertinent to age-associated neurological disorders. Despite the importance of SNARE complex assembly and disassembly in membrane fusion, their diverse localization hinders the complete understanding of their function. Here, we revealed a subset of SNARE proteins, the syntaxin SYX-17, the synaptobrevins VAMP-7, SNB-6 and the tethering factor USO-1, to be either localized or in close proximity to mitochondria, in vivo. We term them mitoSNAREs and show that animals deficient in mitoSNAREs exhibit increased mitochondria mass and accumulation of autophagosomes. The SNARE disassembly factor NSF-1 seems to be required for the effects of mitoSNARE depletion. Moreover, we find mitoSNAREs to be indispensable for normal aging in both neuronal and non-neuronal tissues. Overall, we uncover a previously unrecognized subset of SNAREs that localize to mitochondria and propose a role of mitoSNARE assembly and disassembly factors in basal autophagy regulation and aging.
Collapse
Affiliation(s)
- Ilias Gkikas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013 Heraklion, Crete, Greece
- Department of Biology, School of Sciences and Engineering, University of Crete, 71110 Heraklion, Crete, Greece
| | - Ioanna Daskalaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013 Heraklion, Crete, Greece
- Department of Biology, School of Sciences and Engineering, University of Crete, 71110 Heraklion, Crete, Greece
| | - Konstantinos Kounakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013 Heraklion, Crete, Greece
- Department of Basic Sciences, Faculty of Medicine, University of Crete, 71110 Heraklion, Crete, Greece
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013 Heraklion, Crete, Greece
- Department of Basic Sciences, Faculty of Medicine, University of Crete, 71110 Heraklion, Crete, Greece
- Correspondence: (N.T.); (E.L.)
| | - Eirini Lionaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013 Heraklion, Crete, Greece
- Correspondence: (N.T.); (E.L.)
| |
Collapse
|
3
|
Xu L, Qiu Y, Wang X, Shang W, Bai J, Shi K, Liu H, Liu JP, Wang L, Tong C. ER-mitochondrial contact protein Miga regulates autophagy through Atg14 and Uvrag. Cell Rep 2022; 41:111583. [DOI: 10.1016/j.celrep.2022.111583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 08/10/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022] Open
|
4
|
Koyama-Honda I, Mizushima N. Transient visit of STX17 (syntaxin 17) to autophagosomes. Autophagy 2022; 18:1213-1215. [PMID: 35613317 DOI: 10.1080/15548627.2022.2079337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
STX17 (syntaxin 17) mediates autophagosome-lysosome fusion, and the translocation of STX17 to autophagosomes is characteristic of this process. STX17 arrives at autophagosomes when they are closed, stays there for approximately 10 min to promote fusion with lysosomes, and leaves when the autolysosomes are mature. However, the mechanism of this transient visit remains largely unknown. Here, we summarize the current knowledge about this phenomenon, including a recently discovered retrieval mechanism, and discuss remaining questions.Abbreviations: MAM: mitochondria-associated membrane; SNX: sorting nexin; STX17: syntaxin 17.
Collapse
Affiliation(s)
- Ikuko Koyama-Honda
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
| |
Collapse
|
5
|
First person – Shun Kato. J Cell Sci 2021. [DOI: 10.1242/jcs.259565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ABSTRACT
First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Shun Kato is first author on ‘ Syntaxin 17, an ancient SNARE paralog, plays different and conserved roles in different organisms’, published in JCS. Shun is a master's student in the lab of Mitsuo Tagaya at the School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Japan, investigating organelle communication in mammalian cells.
Collapse
|