SSR2 belongs to the TRAP-beta family. SSR is a glycosylated endoplasmic reticulum (ER) membrane receptor associated with protein translocation across the ER membrane. TRAP proteins are part of a complex whose function is to bind calcium to the ER membrane and thereby regulate the retention of ER resident proteins. The SSR consists of 2 subunits, a 34kD glycoprotein (alpha-SSR or SSR1) and a 22kD glycoprotein (beta-SSR or SSR2)..