Type II transmembrane domain hydrophobicity dictates the cotranslational dependence for inversion.

ABSTRACT: Membrane insertion by the Sec61 translocon in the endoplasmic reticulum (ER) is highly dependent on hydrophobicity. This places stringent hydrophobicity requirements on transmembrane domains (TMDs) from single-spanning membrane proteins. On examining the single-spanning influenza A membrane proteins, we found that the strict hydrophobicity requirement applies to the N(out)-C(in) HA and M2 TMDs but not the N(in)-C(out) TMDs from the type II membrane protein neuraminidase (NA). To investigate this discrepancy, we analyzed NA TMDs of varying hydrophobicity, followed by increasing polypeptide lengths, in mammalian cells and ER microsomes. Our results show that the marginally hydrophobic NA TMDs (ΔG(app) > 0 kcal/mol) require the cotranslational insertion process for facilitating their inversio

SUBMITTER: Dou D 

PROVIDER: S-EPMC4214783 | biostudies-literature | 2014 Nov

REPOSITORIES: biostudies-literature