Sec61? facilitates the maintenance of endoplasmic reticulum homeostasis by associating microtubules.

ABSTRACT: Sec61?, a subunit of the Sec61 translocon complex, is not essential in yeast and commonly used as a marker of endoplasmic reticulum (ER). In higher eukaryotes, such as Drosophila, deletion of Sec61? causes lethality, but its physiological role is unclear. Here, we show that Sec61? interacts directly with microtubules. Overexpression of Sec61? containing small epitope tags, but not a RFP tag, induces dramatic bundling of the ER and microtubule. A basic region in the cytosolic domain of Sec61? is critical for microtubule association. Depletion of Sec61? induces ER stress in both mammalian cells and Caenorhabditis elegans, and subsequent restoration of ER homeostasis correlates with the microtubule binding ability of Sec61?. Loss of Sec61? causes increased mobility of translocon complexes and reduced level of membrane-bound ribosomes. These results suggest that Sec61? may stabilize protein translocation by linking translocon complex to microtubule and provide insight into the physiological function of ER-microtubule interaction.

SUBMITTER: Zhu Y 

PROVIDER: S-EPMC6019657 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature