Evidence that the kinase-truncated c-Src regulates NF-κB signaling by targeting NEMO
Article first published online: 18 AUG 2011
Copyright © 2011 Wiley-Liss, Inc.
Journal of Cellular Biochemistry
Volume 112, Issue 9, pages 2463–2470, September 2011
How to Cite
Dai, S., Abu-Amer, W., Karuppaiah, K. and Abu-Amer, Y. (2011), Evidence that the kinase-truncated c-Src regulates NF-κB signaling by targeting NEMO. J. Cell. Biochem., 112: 2463–2470. doi: 10.1002/jcb.23170
- Issue published online: 18 AUG 2011
- Article first published online: 18 AUG 2011
- Accepted manuscript online: 2 MAY 2011 06:55AM EST
- Manuscript Accepted: 25 APR 2011
- Manuscript Received: 15 FEB 2011
- National Institutes of Health. Grant Numbers: AR049192, AR054326
- Shriners Hospital for Children. Grant Numbers: 8570, 8510
The tyrosine kinase c-Src and transcription factor NF-κB are considered crucial components required for normal osteoclastogenesis. Genetic ablation of either pathway leads to detrimental osteopetrotic phenotypes in mice. Similarly, obstruction of either pathway halts osteoclastogenesis and lessens various forms of bone loss. It has been shown previously that mice expressing a kinase domain-truncated c-Src, termed Src251, develop severe osteopetrosis owing to increased osteoclast apoptosis. It was further suggested that this phenomenon is associated with reduced Akt kinase activity. However, the precise mechanism underlying the osteoclast inhibitory effect of Src251 remains obscure. C-Src associates with TRAF6-p62 interacting with receptor activator of NF-κB (RANK) distal region and the complex facilitate activation of RANK down stream signal transduction cascades including NF-κB. Given this proximity between c-Src and NF-κB signaling in osteoclasts, we surmised that inhibition of osteoclastogenesis by Src251 may be achieved through inhibition of NF-κB signaling. We have demonstrated recently that NEMO, the regulatory subunit of the IKK complex, is crucial for osteoclastogenesis and interacts with c-Src in osteoclast progenitors. Transfection studies, in which we employed various forms of c-Src and NEMO, revealed that the dominant negative form of c-Src, namely Src251, mediates degradation of NEMO thus halting NF-κB signaling. Furthermore, degradation of NEMO requires its intact zinc finger domain which is located at the ubiquitination domain. This process also requires appropriate cellular localization of Src251, since deletion of its myristoylation domain ablates its degradation capacity. Buttressing these findings, the expression of NEMO and NF-κB signaling were significantly reduced in monocytes collected from Src251 transgenic mice. J. Cell. Biochem. 112: 2463–2470, 2011. © 2011 Wiley-Liss, Inc.