Essential component of the signal peptidase complex (SPC) which catalyzes the cleavage of N-terminal signal sequences from nascent proteins as they are translocated into the lumen of the endoplasmic reticulum (PubMed:27499293, PubMed:34388369). Essential for the SPC catalytic activity, possibly by stabilizing and positioning the active center of the complex close to the lumenal surface (By similarity). ; (Microbial infection) Plays an important role in virion production of flaviviruses such as West Nile virus, Japanese enchephalitis virus, Dengue virus type 2 and Yellow Fever virus.
