Sec61B

SEC61B is a human gene that encodes the beta subunit of the Sec61 translocon, a core component of the protein-conducting channel in the endoplasmic reticulum (ER) membrane. The Sec61 translocon is a conserved, heterotrimeric complex that also includes the alpha (Sec61A) and gamma (Sec61G) subunits, and it forms the primary gateway for nascent polypeptides entering the ER during protein synthesis. The beta subunit is a small membrane protein that contributes to the assembly and stability of the translocon and can influence the channel’s properties.

Functionally, the Sec61 complex mediates the translocation of secretory and membrane proteins into the ER, as well as the lateral insertion of hydrophobic segments into the lipid bilayer. The beta subunit, by participating in complex stability, supports efficient translocation and proper ER quality control, and it may affect gating and interactions with other translocation-associated factors.

SEC61B is broadly expressed in human tissues and localizes to the ER membrane as part of the Sec61 translocon. The complex operates in coordination with ribosomes and other translocation machinery to coordinate protein entry into the ER lumen or membrane.

Clinical significance relating specifically to SEC61B is not well defined in the literature. More generally, defects or stress in the Sec61 translocon can impact protein folding and ER homeostasis, with potential downstream effects on cellular function. The Sec61 complex, including the beta subunit, is evolutionarily conserved across eukaryotes, reflecting its essential role in cellular protein processing.