Protein transport protein Sec61 subunit beta

Component of SEC61 channel-forming translocon complex that mediates transport of signal peptide-containing precursor polypeptides across the endoplasmic reticulum (ER). Component of a ribosome-associated ER translocon complex involved in multi-pass membrane protein transport into the ER membrane and biogenesis. The SEC61 channel cooperates with the translocating protein TRAM1 to import nascent proteins into the ER. Required for PKD1/Polycystin-1 biogenesis (By similarity).