Nucleotide exchange factor SIL1 is a protein encoded in humans by the SIL1 gene.
This gene encodes a resident endoplasmic reticulum (ER) N-linked glycoprotein with an N-terminal ER targeting sequence, two putative N-glycosylation sites, and a C-terminal ER retention signal. This protein functions as a nucleotide exchange factor for another unfolded protein response protein. Mutations in this gene have been associated with Marinesco-Sjogren syndrome. Alternative transcriptional splice variants have been characterized.