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SIL1 gene

SIL1 nucleotide exchange factor

Normal Function

The SIL1 gene provides instructions for producing a protein located in a cell structure called the endoplasmic reticulum. Among its many functions, the endoplasmic reticulum folds and modifies newly formed proteins so they have the correct 3-dimensional shape. The SIL1 protein works with BiP, a protein that helps fold newly produced proteins into the proper shape and refold damaged proteins. To start this process, BiP attaches (binds) to a molecule called adenosine triphosphate (ATP). When BiP folds a protein, the ATP is converted to a similar molecule called adenosine diphosphate (ADP). Then the SIL1 protein releases ADP from BiP so that it can bind to another molecule of ATP and start the protein folding process again. Because of its role in helping BiP exchange ADP for ATP, the SIL1 protein is called a nucleotide exchange factor.

Health Conditions Related to Genetic Changes

Marinesco-Sjögren syndrome

More than a dozen mutations in the SIL1 gene have been found to cause Marinesco-Sjögren syndrome. Most of these mutations result in the production of a protein that has little or no activity. Defective SIL1 protein cannot remove ADP from BiP. BiP is then unable to bind to ATP and re-start the protein folding process. A disruption in protein folding impairs protein transport and causes proteins to accumulate in the endoplasmic reticulum. This accumulation likely damages and destroys cells in many different tissues, leading to poor coordination, muscle weakness, and the other features of Marinesco-Sjögren syndrome.

More About This Health Condition

Other Names for This Gene

  • BAP
  • BiP-associated protein
  • MSS
  • SIL1 homolog, endoplasmic reticulum chaperone (S. cerevisiae)
  • SIL1 protein
  • ULG5

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Anttonen AK, Mahjneh I, Hamalainen RH, Lagier-Tourenne C, Kopra O, Waris L, Anttonen M, Joensuu T, Kalimo H, Paetau A, Tranebjaerg L, Chaigne D, Koenig M, Eeg-Olofsson O, Udd B, Somer M, Somer H, Lehesjoki AE. The gene disrupted in Marinesco-Sjogren syndrome encodes SIL1, an HSPA5 cochaperone. Nat Genet. 2005 Dec;37(12):1309-11. doi: 10.1038/ng1677. Epub 2005 Nov 13. Citation on PubMed
  • Anttonen AK, Siintola E, Tranebjaerg L, Iwata NK, Bijlsma EK, Meguro H, Ichikawa Y, Goto J, Kopra O, Lehesjoki AE. Novel SIL1 mutations and exclusion of functional candidate genes in Marinesco-Sjogren syndrome. Eur J Hum Genet. 2008 Aug;16(8):961-9. doi: 10.1038/ejhg.2008.22. Epub 2008 Feb 20. Citation on PubMed
  • Eriguchi M, Mizuta H, Kurohara K, Fujitake J, Kuroda Y. Identification of a new homozygous frameshift insertion mutation in the SIL1 gene in 3 Japanese patients with Marinesco-Sjogren syndrome. J Neurol Sci. 2008 Jul 15;270(1-2):197-200. doi: 10.1016/j.jns.2008.02.012. Epub 2008 Apr 18. Citation on PubMed
  • Senderek J, Krieger M, Stendel C, Bergmann C, Moser M, Breitbach-Faller N, Rudnik-Schoneborn S, Blaschek A, Wolf NI, Harting I, North K, Smith J, Muntoni F, Brockington M, Quijano-Roy S, Renault F, Herrmann R, Hendershot LM, Schroder JM, Lochmuller H, Topaloglu H, Voit T, Weis J, Ebinger F, Zerres K. Mutations in SIL1 cause Marinesco-Sjogren syndrome, a cerebellar ataxia with cataract and myopathy. Nat Genet. 2005 Dec;37(12):1312-4. doi: 10.1038/ng1678. Epub 2005 Nov 13. Citation on PubMed
  • Van Raamsdonk JM. Loss of function mutations in SIL1 cause Marinesco-Sjogren syndrome. Clin Genet. 2006 May;69(5):399-400. doi: 10.1111/j.1399-0004.2006.00595a.x. No abstract available. Citation on PubMed
  • Zimmermann R, Muller L, Wullich B. Protein transport into the endoplasmic reticulum: mechanisms and pathologies. Trends Mol Med. 2006 Dec;12(12):567-73. doi: 10.1016/j.molmed.2006.10.004. Epub 2006 Oct 30. Citation on PubMed
  • Zoghbi HY. SILencing misbehaving proteins. Nat Genet. 2005 Dec;37(12):1302-3. doi: 10.1038/ng1205-1302. No abstract available. Citation on PubMed

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.