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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®

SKOR gene family

Reviewed February 2013

What are the SKOR genes?

Genes in the SKOR gene family provide instructions for making proteins called SKI transcriptional corepressors. These proteins are able to stop (repress) the first step in the production of proteins from genes, a process known as gene transcription. They repress transcription by blocking signaling pathways that turn on gene activity, in particular the transforming growth factor beta (TGF-β) pathway and the bone morphogenic protein (BMP) pathway.

Signaling through the TGF-β and BMP pathways turns on (activates) proteins called SMADs, which combine to form a protein complex. The activated SMAD protein complex moves to the nucleus and attaches (binds) to specific areas of DNA to activate gene transcription. The TGF-β and BMP pathways are able to regulate various cellular processes, including cell growth and division (proliferation), the process by which cells mature to carry out special functions (differentiation), and the self-destruction of cells (apoptosis).

SKI transcriptional corepressors control the activity of the TGF-β and BMP pathways by attaching (binding) to certain SMAD proteins, which interrupts signaling through the pathways. SKI transcriptional corepressor binding within the cell can keep the SMAD protein complex from entering the nucleus, so it is unable to control gene activity. Binding of the SKI transcriptional corepressor can also occur in the nucleus, where it allows the SMAD protein complex to attach to DNA, but blocks its ability to turn genes on.

The SKI transcriptional corepressors are important during development and throughout life. The SKI and SKIL proteins, two members of this family, are found in many cell types throughout the body and appear to play a role in the development of many tissues, including bones, muscles, and the brain. Mutations in the SKI gene lead to a disorder called Shprintzen-Goldberg syndrome, which affects many parts of the body and is characterized by distinctive facial features and skeletal and neurological abnormalities. Two other SKI transcriptional corepressors, SKOR1 and SKOR2, are found only in the nervous system, particularly in a region of the brain called the cerebellum. These proteins appear to be important for proper development of this part of the brain.

Which genes are included in the SKOR gene family?

The HUGO Gene Nomenclature Committee (HGNC) provides an index of gene families ( and their member genes.

Genetics Home Reference summarizes the normal function and health implications of this member of the SKOR gene family: SKI.

What conditions are related to genes in the SKOR gene family?

Genetics Home Reference includes these conditions related to genes in the SKOR gene family:

  • Shprintzen-Goldberg syndrome

Where can I find additional information about the SKOR gene family?

You may find the following resources about the SKOR gene family helpful.

  • Developmental Biology (sixth edition, 2000): The Smad Pathway Activated by TGF-β Superfamily Ligands (
  • Genomes (second edition, 2002): SMAD Signaling in Vertebrates (
  • Molecular Biology of the Cell (fourth edition, 2002): Signal Proteins of the TGF-β Superfamily Act Through Receptor Serine/Threonine Kinases and Smads (

What glossary definitions help with understanding the SKOR gene family?

apoptosis ; cell ; cerebellum ; corepressor ; differentiation ; DNA ; gene ; gene transcription ; growth factor ; nervous system ; neurological ; nucleus ; oncogene ; proliferation ; protein ; proto-oncogene ; syndrome ; transcription

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


These sources were used to develop the Genetics Home Reference summary for the SKOR gene family.

  • Wang B, Harrison W, Overbeek PA, Zheng H. Transposon mutagenesis with coat color genotyping identifies an essential role for Skor2 in sonic hedgehog signaling and cerebellum development. Development. 2011 Oct;138(20):4487-97. doi: 10.1242/dev.067264. (
  • Deheuninck J, Luo K. Ski and SnoN, potent negative regulators of TGF-beta signaling. Cell Res. 2009 Jan;19(1):47-57. doi: 10.1038/cr.2008.324. Review. (
  • Arndt S, Poser I, Moser M, Bosserhoff AK. Fussel-15, a novel Ski/Sno homolog protein, antagonizes BMP signaling. Mol Cell Neurosci. 2007 Apr;34(4):603-11. Epub 2007 Jan 11. (
  • Arndt S, Poser I, Schubert T, Moser M, Bosserhoff AK. Cloning and functional characterization of a new Ski homolog, Fussel-18, specifically expressed in neuronal tissues. Lab Invest. 2005 Nov;85(11):1330-41. (
  • Jahchan NS, Luo K. SnoN in mammalian development, function and diseases. Curr Opin Pharmacol. 2010 Dec;10(6):670-5. doi: 10.1016/j.coph.2010.08.006. Epub 2010 Sep 6. Review. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: February 2013
Published: February 8, 2016