InterPro domain: IPR030671

A conserved heterotrimeric integral membrane protein complex--the Sec61 complex (eukaryotes) or SecY complex (prokaryotes)--forms a protein-conducting channel that allows polypeptides to be transferred across (or integrated into) the endoplasmic reticulum (eukaryotes) or across the cytoplasmic membrane (prokaryotes) [ 1 , 2 ]. This complex is itself a part of a larger translocase complex.

The alpha subunits ( IPR002208 ), called Sec61alpha in mammals, Sec61p in Saccharomyces cerevisiae (Baker's yeast), and SecY in prokaryotes, and the gamma subunits, called Sec61gamma in mammals, Sss1p in S. cerevisiae, and SecE in prokaryotes, show significant sequence conservation. Both subunits are required for cell viability in S. cerevisiae and Escherichia coli. The beta subunits, called Sec61beta in mammals, Sbh in S. cerevisiae, and SecG in archaea, are not essential for cell viability. They are similar in eukaryotes and archaea, but show no obvious homology to the corresponding SecG subunits in bacteria.

This family includes Sec61 subunit beta, Sbh1 and Sbh2 from the eukaryotic Sec61 complex.

1. X-ray structure of a protein-conducting channel. Nature 427, 36-44
2. The Sec protein-translocation pathway. Trends Microbiol. 9, 494-500