TRAM1 protein may support ER protein import by modulating the phospholipid bilayer near the lateral gate of the Sec61-channel.

ABSTRACT: In mammalian cells, one-third of all polypeptides is transported into or through the ER-membrane via the Sec61-channel. While the Sec61-complex facilitates the transport of all polypeptides with amino-terminal signal peptides (SP) or SP-equivalent transmembrane helices (TMH), the translocating chain-associated membrane protein (now termed TRAM1) was proposed to support transport of a subset of precursors. To identify possible determinants of TRAM1 substrate specificity, we systematically identified TRAM1-dependent precursors by analyzing cellular protein abundance changes upon TRAM1 depletion in HeLa cells using quantitative label-free proteomics. In contrast to previous analysis after TRAP depletion, SP and TMH analysis of TRAM1 clients did not reveal any distinguishing features that coul

SUBMITTER: Klein MC 

PROVIDER: S-EPMC7039644 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature