The Get1/2 insertase forms a channel to mediate the insertion of tail-anchored proteins into the ER

Autor: Paul Heo, Jacob A. Culver, Jennifer Miao, Frederic Pincet, Malaiyalam Mariappan
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Cell Reports, Vol 42, Iss 1, Pp 111921- (2023)
Druh dokumentu: article
ISSN: 2211-1247
DOI: 10.1016/j.celrep.2022.111921
Popis: Summary: Tail-anchored (TA) proteins contain a single C-terminal transmembrane domain (TMD) that is captured by the cytosolic Get3 in yeast (TRC40 in humans). Get3 delivers TA proteins to the Get1/2 complex for insertion into the endoplasmic reticulum (ER) membrane. How Get1/2 mediates insertion of TMDs of TA proteins into the membrane is poorly understood. Using bulk fluorescence and microfluidics assays, we show that Get1/2 forms an aqueous channel in reconstituted bilayers. We estimate the channel diameter to be ∼2.5 nm wide, corresponding to the circumference of two Get1/2 complexes. We find that the Get3 binding can seal the Get1/2 channel, which dynamically opens and closes. Our mutation analysis further shows that the Get1/2 channel activity is required to release TA proteins from Get3 for insertion into the membrane. Hence, we propose that the Get1/2 channel functions as an insertase for insertion of TMDs and as a translocase for translocation of C-terminal hydrophilic segments.
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