Inflammatory bowel disease reveals the kinase activity of KSR1 Article Report uri icon


MeSH Major

  • Apoptosis
  • Neoplasms


  • Kinase suppressor of Ras-1 (KSR1) is a recently identified member of the EGFR-Ras-Raf-1-MAPK signaling pathway. A new study demonstrates that KSR1 protects intestinal epithelium from TNF-alpha-induced apoptosis, abrogating inflammatory bowel disease (IBD). Since its discovery, there has been disagreement as to whether KSR1 possesses intrinsic kinase activity. Using transgenic mouse models and genetically modified mouse colon epithelial cells, Polk and coworkers show that the kinase activity of KSR1 is off in normal colon epithelial cells, becoming activated only at the onset of IBD. They also provide strong evidence that KSR1 kinase activity is essential for anti-apoptotic protection of the intestinal epithelium. These new data in support of KSR1 as a kinase highlight an ongoing debate as to whether KSR1 does indeed serve as a specific kinase in transphosphorylating and transactivating c-Raf-1 toward MEK1.

publication date

  • November 2004



  • Report


Digital Object Identifier (DOI)

  • 10.1172/JCI200423441

PubMed ID

  • 15520853

Additional Document Info

start page

  • 1233

end page

  • 7


  • 114


  • 9