The heterodimeric receptor for the signal recognition particle (SRP) in the membrane of the endoplasmic reticulum (ER). Both protomers have GTP-binding capacity. Once the SRP, mRNA, ribosome, and nascent polypeptide bind the SRP receptor the block to translation is lifted and the SRP is released. The growing polypeptide is cotranslationally transported to the lumen of the ER.
Subjects: Chemistry — Medicine and Health.