| 1. |
- Corkery, Dale, et al.
(författare)
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An ATG12-ATG5-TECPR1 E3-like complex regulates unconventional LC3 lipidation at damaged lysosomes
- 2023
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Ingår i: EMBO Reports. - : EMBO Press. - 1469-221X .- 1469-3178. ; 24:9
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Tidskriftsartikel (refereegranskat)abstract
- Lysosomal membrane damage represents a threat to cell viability. As such, cells have evolved sophisticated mechanisms to maintain lysosomal integrity. Small membrane lesions are detected and repaired by the endosomal sorting complex required for transport (ESCRT) machinery while more extensively damaged lysosomes are cleared by a galectin-dependent selective macroautophagic pathway (lysophagy). In this study, we identify a novel role for the autophagosome-lysosome tethering factor, TECPR1, in lysosomal membrane repair. Lysosomal damage promotes TECPR1 recruitment to damaged membranes via its N-terminal dysferlin domain. This recruitment occurs upstream of galectin and precedes the induction of lysophagy. At the damaged membrane, TECPR1 forms an alternative E3-like conjugation complex with the ATG12-ATG5 conjugate to regulate ATG16L1-independent unconventional LC3 lipidation. Abolishment of LC3 lipidation via ATG16L1/TECPR1 double knockout impairs lysosomal recovery following damage.
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| 2. |
- Jia, Xiaotong, et al.
(författare)
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V. cholerae MakA is a cholesterol-binding pore-forming toxin that induces non-canonical autophagy
- 2022
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Ingår i: Journal of Cell Biology. - : Rockefeller University Press. - 0021-9525 .- 1540-8140. ; 221:12
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Tidskriftsartikel (refereegranskat)abstract
- Pore-forming toxins (PFTs) are important virulence factors produced by many pathogenic bacteria. Here, we show that the Vibrio cholerae toxin MakA is a novel cholesterol-binding PFT that induces non-canonical autophagy in a pH-dependent manner. MakA specifically binds to cholesterol on the membrane at pH < 7. Cholesterol-binding leads to oligomerization of MakA on the membrane and pore formation at pH 5.5. Unlike other cholesterol-dependent cytolysins (CDCs) which bind cholesterol through a conserved cholesterol-binding motif (Thr-Leu pair), MakA contains an Ile-Ile pair that is essential for MakA-cholesterol interaction. Following internalization, endosomal acidification triggers MakA pore-assembly followed by ESCRT-mediated membrane repair and V-ATPase-dependent unconventional LC3 lipidation on the damaged endolysosomal membranes. These findings characterize a new cholesterol-binding toxin that forms pores in a pH-dependent manner and reveals the molecular mechanism of host autophagy manipulation.
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| 3. |
- Knyazeva, Anastasia, 1995-, et al.
(författare)
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A chemical inhibitor of IST1-CHMP1B interaction impairs endosomal recycling and induces noncanonical LC3 lipidation
- 2024
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 121:17
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Tidskriftsartikel (refereegranskat)abstract
- The endosomal sorting complex required for transport (ESCRT) machinery constitutes multisubunit protein complexes that play an essential role in membrane remodeling and trafficking. ESCRTs regulate a wide array of cellular processes, including cytokinetic abscission, cargo sorting into multivesicular bodies (MVBs), membrane repair, and autophagy. Given the versatile functionality of ESCRTs, and the intricate organizational structure of the ESCRT machinery, the targeted modulation of distinct ESCRT complexes is considerably challenging. This study presents a pseudonatural product targeting IST1-CHMP1B within the ESCRT-III complexes. The compound specifically disrupts the interaction between IST1 and CHMP1B, thereby inhibiting the formation of IST1-CHMP1B copolymers essential for normal-topology membrane scission events. While the compound has no impact on cytokinesis, MVB sorting, or biogenesis of extracellular vesicles, it rapidly inhibits transferrin receptor recycling in cells, resulting in the accumulation of transferrin in stalled sorting endosomes. Stalled endosomes become decorated by lipidated LC3, suggesting a link between noncanonical LC3 lipidation and inhibition of the IST1-CHMP1B complex.
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| 4. |
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| 5. |
- Knyazeva, Anastasia, 1995-
(författare)
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Non-canonical ATG8 conjugation in ESCRT-driven membrane remodeling processes
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- ATG8 family proteins have the unique ability to conjugate to membrane lipids. Initially identified as a hallmark of autophagy, ATG8 lipidation is emerging as an important regulator of a growing list of non-degradative cellular functions. In this thesis we developed and applied novel chemical genetic approaches to perturb dynamic membrane remodeling processes and induce non-canonical ATG8 conjugation in cells. We investigated novel roles of ATG8 in membrane deformation processes carried out by the Endosomal Sorting Complex Requiredfor Transport (ESCRT) machinery.In Paper I, using a high-throughput phenotypic screening assay, we developed a collection of pseudo-natural product-based compounds which potently induce ATG8 lipidation in mammalian cells. The most potent compound, Tantalosin, induces ATG8 lipidation which is insensitive to simultaneous inhibition of autophagosome-lysosome fusion, suggesting a non-canonical function ofTantalosin-induced ATG8 conjugation.In Paper II we investigated the molecular target of Tantalosin. We found that Tantalosin targets the ESCRT-III protein IST1 and inhibits IST1-CHMP1B copolymer formation. This inhibition results in the impairment of transferrin receptor (TfR) recycling resulting in the rapid accumulation of the receptor inearly/sorting endosomes. At the same time, Tantalosin induces non-canonical ATG8 conjugation on stalled sorting endosomes containing TfR. This conjugation is dependent on the ATG16L1-ATG5-ATG12 complex which is recruited to stalled endosomes via ATG16L1-V-ATPase interaction.In Paper III and Paper IV we studied the induction of non-canonical ATG8 lipidation in response to endolysosomal membrane damage. We used two established membrane damaging agents: V. Cholerae cytotoxin MakA and the lysosomotropic compound, LLOMe. In Paper III we demonstrated that, at lowpH, MakA assembles into small pores in endosomal membranes which arerecognized by the ESCRT membrane repair machinery. Non-canonical ATG8 lipidation in response to MakA-induced pore formation is mediated by V-ATPase activity. In Paper IV we identified a novel player in the lysosomal damage response – TECRP1. TECPR1 is recruited to damaged membranes where it forms an alternative ATG16L1-independent E3 ligase complex with the ATG5-ATG12 conjugate and plays a role in the restoration of lysosomal integrity after damage.
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| 6. |
- Niggemeyer, Georg, et al.
(författare)
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Synthesis of 20-Membered Macrocyclic Pseudo-Natural Products Yields Inducers of LC3 Lipidation
- 2022
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Ingår i: Angewandte Chemie International Edition. - : Wiley-VCH Verlagsgesellschaft. - 1433-7851 .- 1521-3773. ; 61:11
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Tidskriftsartikel (refereegranskat)abstract
- Design and synthesis of pseudo-natural products (PNPs) through recombination of natural product (NP) fragments in unprecedented arrangements enables the discovery of novel biologically relevant chemical matter. With a view to wider coverage of NP-inspired chemical and biological space, we describe the combination of this principle with macrocycle formation. PNP-macrocycles were synthesized efficiently in a stereoselective one-pot procedure including the 1,3-dipolar cycloadditions of different dipolarophiles with dimeric cinchona alkaloid-derived azomethine ylides formed in situ. The 20-membered bis-cycloadducts embody 18 stereocenters and an additional fragment-sized NP-structure. After further functionalization, a collection of 163 macrocyclic PNPs was obtained. Biological investigation revealed potent inducers of the lipidation of the microtubule associated protein 1 light chain 3 (LC3) protein, which plays a prominent role in various autophagy-related processes.
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