Signal Peptidase Complex Subunit 3 Homolog (SPCS3)

Component of the microsomal signal peptidase complex which consists of five members: SEC11A, SEC11C, SPCS1, SPCS2  and SPCS3 . Component of the microsomal signal peptidase complex which removes signal peptides from nascent proteins as they are translocated into the lumen of the endoplasmic reticulum.Signal peptidases are enzymes that convert secretory and some membrane proteins to their mature form by cleaving off their N-terminal targeting signals.Signal peptidases were initially observed in endoplasmic reticulum (ER)-derived membrane fractions isolated from mouse myeloma cells. The key observation by César Milstein and colleagues was that immunoglobulin light chains were produced in a higher molecular weight form, which became processed by the ER membrane fraction.