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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.
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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
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Zhu Y, Liu F, Jian F, Rong Y. Recent progresses in the late stages of autophagy. CELL INSIGHT 2024; 3:100152. [PMID: 38435435 PMCID: PMC10904915 DOI: 10.1016/j.cellin.2024.100152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 01/30/2024] [Accepted: 01/30/2024] [Indexed: 03/05/2024]
Abstract
Autophagy, a lysosome-dependent degradation process, plays a crucial role in maintaining cell homeostasis. It serves as a vital mechanism for adapting to stress and ensuring intracellular quality control. Autophagy deficiencies or defects are linked to numerous human disorders, especially those associated with neuronal degeneration or metabolic diseases. Yoshinori Ohsumi was honored with the Nobel Prize in Physiology or Medicine in 2016 for his groundbreaking discoveries regarding autophagy mechanisms. Over the past few decades, autophagy research has predominantly concentrated on the early stages of autophagy, with relatively limited attention given to the late stages. Nevertheless, recent studies have witnessed substantial advancements in understanding the molecular intricacies of the late stages, which follows autophagosome formation. This review provides a comprehensive summary of the recent progresses in comprehending the molecular mechanisms of the late stages of autophagy.
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Affiliation(s)
- YanYan Zhu
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, China
- Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Fengping Liu
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, China
- Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Fenglei Jian
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, China
- Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yueguang Rong
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, China
- Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan, Hubei, China
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Jian F, Wang S, Tian R, Wang Y, Li C, Li Y, Wang S, Fang C, Ma C, Rong Y. The STX17-SNAP47-VAMP7/VAMP8 complex is the default SNARE complex mediating autophagosome-lysosome fusion. Cell Res 2024; 34:151-168. [PMID: 38182888 PMCID: PMC10837459 DOI: 10.1038/s41422-023-00916-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 12/11/2023] [Indexed: 01/07/2024] Open
Abstract
Autophagosome-lysosome fusion mediated by SNARE complexes is an essential step in autophagy. Two SNAP29-containing SNARE complexes have been extensively studied in starvation-induced bulk autophagy, while the relevant SNARE complexes in other types of autophagy occurring under non-starvation conditions have been overlooked. Here, we found that autophagosome-lysosome fusion in selective autophagy under non-starvation conditions does not require SNAP29-containing SNARE complexes, but requires the STX17-SNAP47-VAMP7/VAMP8 SNARE complex. Further, the STX17-SNAP47-VAMP7/VAMP8 SNARE complex also functions in starvation-induced autophagy. SNAP47 is recruited to autophagosomes following concurrent detection of ATG8s and PI(4,5)P2 via its Pleckstrin homology domain. By contrast, SNAP29-containing SNAREs are excluded from selective autophagy due to inactivation by O-GlcNAcylation under non-starvation conditions. These findings depict a previously unknown, default SNARE complex responsible for autophagosome-lysosome fusion in both selective and bulk autophagy, which could guide research and therapeutic development in autophagy-related diseases.
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Affiliation(s)
- Fenglei Jian
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Shen Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Rui Tian
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yufen Wang
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Chuangpeng Li
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yan Li
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Shixuan Wang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Chao Fang
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Cong Ma
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China.
| | - Yueguang Rong
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, Hubei, China.
- Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan, Hubei, China.
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