ESCRTs Cooperate with a Selective Autophagy Receptor to Mediate Vacuolar Targeting of Soluble Cargos

Liu, Xiaoman; Sun, Lingling; Hu, Wen; Ding, Yue-He; Dong, Meng‐Qiu; Du, Li-Lin

doi:10.1016/j.molcel.2015.07.034

Cited by 96 publications

(135 citation statements)

References 38 publications

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“…Then, the mixtures were cross‐linked with the indicated amount BS 3 or disuccinimidyl suberate (protein: DSS with a molar ratio of 1:50) at room temperature for 1 h. As previously described , after being quenched with 20 mM NH 4 HCO 3 , the resulting products were precipitated and digested with trypsin. The LC‐MS/MS analysis was performed on an Easy‐nLC 1000 HPLC coupled to a Q Exactive‐Orbitrap mass spectrometer (Thermo Fisher Scientific) . Cross‐linked 14 N‐peptides were identified using pLink with a FDR of 5% and E ‐value < 0.001.…”

Section: Methodsmentioning

confidence: 99%

Structural basis for receptor recognition and pore formation of a zebrafish aerolysin‐like protein

et al. 2015

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Various aerolysin-like pore-forming proteins have been identified from bacteria to vertebrates. However, the mechanism of receptor recognition and/or pore formation of the eukaryotic members remains unknown. Here, we present the first crystal and electron microscopy structures of a vertebrate aerolysin-like protein from Danio rerio, termed Dln1, before and after pore formation. Each subunit of Dln1 dimer comprises a b-prism lectin module followed by an aerolysin module. Specific binding of the lectin module toward high-mannose glycans triggers drastic conformational changes of the aerolysin module in a pH-dependent manner, ultimately resulting in the formation of a membrane-bound octameric pore. Structural analyses combined with computational simulations and biochemical assays suggest a pore-forming process with an activation mechanism distinct from the previously characterized bacterial members. Moreover, Dln1 and its homologs are ubiquitously distributed in bony fishes and lamprey, suggesting a novel fish-specific defense molecule.

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Section: Methodsmentioning

confidence: 99%

Structural basis for receptor recognition and pore formation of a zebrafish aerolysin‐like protein

et al. 2015

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“…This suggests that Pub1 contributes to the degradation of Sec3-913. Because double deletion mutants of pub1, pub2, and pub3 display synthetically sick/lethal phenotypes (43,44), we did not construct pub double mutants in the sec3-913 background.…”

Section: The Sec3-913 Temperature Sensitivity Is Partially Suppressedmentioning

confidence: 99%

The exocyst subunit Sec3 is regulated by a protein quality control pathway

Kampmeyer

Karakostova

Schenstrøm

et al. 2017

Journal of Biological Chemistry

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Exocytosis involves fusion of secretory vesicles with the plasma membrane, thereby delivering membrane proteins to the cell surface and releasing material into the extracellular space. The tethering of the secretory vesicles before membrane fusion is mediated by the exocyst, an essential phylogenetically conserved octameric protein complex. Exocyst biogenesis is regulated by several processes, but the mechanisms by which the exocyst is degraded are unknown. Here, to unravel the components of the exocyst degradation pathway, we screened for extragenic suppressors of a temperature-sensitive fission yeast strain mutated in the exocyst subunit Sec3 (). One of the suppressing DNAs encoded a truncated dominant-negative variant of the 26S proteasome subunit, Rpt2, indicating that exocyst degradation is controlled by the ubiquitin-proteasome system. The temperature-dependent growth defect of the strain was gene dosage-dependent and suppressed by blocking the proteasome, Hsp70-type molecular chaperones, the Pib1 E3 ubiquitin-protein ligase, and the deubiquitylating enzyme Ubp3. Moreover, defects in cell septation, exocytosis, and endocytosis in mutant strains were similarly alleviated by mutation of components in this pathway. We also found that, particularly under stress conditions, wild-type Sec3 degradation is regulated by Pib1 and the 26S proteasome. In conclusion, our results suggest that a cytosolic protein quality control pathway monitors folding and proteasome-dependent turnover of an exocyst subunit and, thereby, controls exocytosis in fission yeast.

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“…Specifically, the Vps34-ESCRT-0 axis plays a key role in regulating proteostasis of CryAB. Although the canonical cargos of the MVB pathway are membrane proteins, recent studies have proposed a new type of autophagy called endosomal microautophagy, by which soluble cytosolic proteins are incorporated into intraluminal vesicles of MVBs in ESCRTdependent manners (33)(34)(35). ESCRT-dependent degradation of the nontransmembrane protein CryAB revealed in this study demonstrates the physiological relevance of endosomal microautophagy at a wholeanimal level.…”

Section: Resultsmentioning

confidence: 55%