nucleotide exchange factor SIL1 (BiP-associated protein, BAP, SIL1)

Function

• required for protein translocation & folding in the endoplasmic reticulum (ER)
• nucleotide exchange factor for the ER lumenal chaperone HSPA5

Structure

• belongs to the SIL1 family
• N-glycosylated

Compartment

endoplasmic reticulum lumen

Expression

• highly expressed in tissues which produce large amounts of secreted proteins, i.e. kidney, liver, placenta
• also expressed in colon, heart, lung, ovary, pancreas, peripheral leukocyte, prostate, spleen, thymus
• expressed at low levels throughout the brain
• expressed in fetal kidney, fetal lung, fetal liver & at low levels in fetal brain

Pathology

• defects in SIL1 are a cause of Marinesco-Sjoegren syndrome
• mutational inactivation of SIL1 may result in ER stress- induced cell death signaling or malfunctioning chaperone machineries that mishandle client proteins critical for organs targeted in Marinesco-Sjoegren syndrome

More general terms

• chaperonin; chaperone
• glycoprotein

Database

• OMIM: https://mirror.omim.org/entry/248800
• OMIM: https://mirror.omim.org/entry/608005
• UniProt: http://www.uniprot.org/uniprot/Q9H173.html