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- Yim, Chewon, et al.
(författare)
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Spc1 regulates the signal peptidase-mediated processing of membrane proteins
- 2021
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Ingår i: Journal of Cell Science. - : The Company of Biologists. - 0021-9533 .- 1477-9137. ; 134:13
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Tidskriftsartikel (refereegranskat)abstract
- Signal peptidase (SPase) cleaves the signal sequences (SSs) of secretory precursors. It contains an evolutionarily conserved membrane protein subunit, Spc1, that is dispensable for the catalytic activity of SPase and whose role remains unknown. In this study, we investigated the function of yeast Spc1. First, we set up an in vivo SPase cleavage assay using variants of the secretory protein carboxypeptidase Y (CPY) with SSs modified in the N-terminal and hydrophobic core regions. When comparing the SS cleavage efficiencies of these variants in cells with or without Spc1, we found that signal-anchored sequences became more susceptible to cleavage by SPase without Spc1. Furthermore, SPase-mediated processing of model membrane proteins was enhanced in the absence of Spc1 and was reduced upon overexpression of Spc1. Spc1 co-immunoprecipitated with proteins carrying uncleaved signal-anchored or transmembrane (TM) segments. Taken together, these results suggest that Spc1 protects TM segments from SPase action, thereby sharpening SPase substrate selection and acting as a negative regulator of the SPase-mediated processing of membrane proteins.
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| 2. |
- Lee, Yun-Bin, et al.
(författare)
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Super-resolution proximity labeling reveals anti-viral protein network and its structural changes against SARS-CoV-2 viral proteins
- 2023
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Ingår i: Cell Reports. - : CELL PRESS. - 2211-1247. ; 42:8
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Tidskriftsartikel (refereegranskat)abstract
- Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replicates in human cells by interacting with host factors following infection. To understand the virus and host interactome proximity, we introduce a super-resolution proximity labeling (SR-PL) method with a "plug-and-playable"PL enzyme, TurboID-GBP (GFP-binding nanobody protein), and we apply it for interactome mapping of SARS-CoV-2 ORF3a and mem-brane protein (M), which generates highly perturbed endoplasmic reticulum (ER) structures. Through SR-PL analysis of the biotinylated interactome, 224 and 272 peptides are robustly identified as ORF3a and M inter-actomes, respectively. Within the ORF3a interactome, RNF5 co-localizes with ORF3a and generates ubiquitin modifications of ORF3a that can be involved in protein degradation. We also observe that the SARS-CoV-2 infection rate is efficiently reduced by the overexpression of RNF5 in host cells. The interactome data ob-tained using the SR-PL method are presented at https://sarscov2.spatiomics.org. We hope that our method will contribute to revealing virus-host interactions of other viruses in an efficient manner.
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