Spc1 regulates the signal peptidase-mediated processing of membrane proteins.
J Cell Sci
; 134(13)2021 07 01.
Article
en En
| MEDLINE
| ID: mdl-34125229
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.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Péptido Hidrolasas
/
Serina Endopeptidasas
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Proteínas de Saccharomyces cerevisiae
Idioma:
En
Revista:
J Cell Sci
Año:
2021
Tipo del documento:
Article
País de afiliación:
Corea del Sur