|
Advertisement | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
J. Biol. Chem., Vol. 283, Issue 16, 10339-10346, April 18, 2008
Translational Control of C-terminal Src Kinase (Csk) Expression by PRL3 Phosphatase*From the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202 Phosphatase of regenerating liver 3 (PRL3) is up-regulated in cancer metastases. However, little is known of PRL3-mediated cellular signaling pathways. We previously reported that elevated PRL3 expression increases Src kinase activity, which likely contributes to the increased tumorigenesis and metastasis potential of PRL3. PRL3-induced Src activation is proposed to be indirect through down-regulation of Csk, a negative regulator of Src. Given the importance of PRL3 in tumor metastasis and the role of Csk in controlling Src activity, we addressed the mechanism by which PRL3 mediates Csk down-regulation. PRL3 is shown to exert a negative effect on Csk protein synthesis, rather than regulation of Csk mRNA levels or protein turnover. Interestingly, the preferential decrease in Csk protein synthesis is a consequence of increased eIF2 phosphorylation resulting from PRL3 expression. Reduced Csk synthesis also occurs in response to cellular stress that induces eIF2 phosphorylation, indicating that this regulatory mechanism may occur in response to a wider spectrum of cellular conditions known to direct translational control. Thus, we have uncovered a previously uncharacterized role for PRL3 in the gene-specific translational control of Csk expression.
Received for publication, October 4, 2007 , and in revised form, February 11, 2008. * This work was supported by National Institutes of Health Grants CA69202 and GM49164. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. 1 To whom correspondence should be addressed. E-mail: zyzhang{at}iupui.edu.
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Advertisement | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||