Activation of p38 Mitogen-activated Protein Kinase by PYK2/Related Adhesion Focal Tyrosine Kinase-dependent Mechanism*
- Pramod Pandey,
- Shalom Avraham‡,
- Shailender Kumar,
- Atsuko Nakazawa,
- Andrew Place,
- Louis Ghanem§,
- Ajay Rana§,
- Vijay Kumar,
- Pradip K. Majumder,
- Hava Avraham‡,
- Roger J. Davis¶ and
- Surender Kharbanda‖
- From the Department of Adult Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115,‡Division of Experimental Medicine and Hematology, Deaconess Medical Center, Harvard Institutes of Medicine, Boston, Massachusetts 02115, §Department of Molecular Biology, Diabetes Research Laboratory, Massachusetts General Hospital, Boston, Massachusetts 02114, and ¶Department of Biochemistry and Molecular Biology, Howard Hughes Medical Institute, Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
Abstract
The stress-activated p38 mitogen-activated protein kinase (p38 MAPK), a member of the subgroup of mammalian kinases, appears to play an important role in regulating inflammatory responses, including cytokine secretion and apoptosis. The upstream mediators that link extracellular signals with the p38 MAPK signaling pathway are currently unknown. Here we demonstrate that pp125 focal adhesion kinase-related tyrosine kinase RAFTK (also known as PYK2, CADTK) is activated specifically by methylmethane sulfonate (MMS) and hyperosmolarity but not by ultraviolet radiation, ionizing radiation, or cis-platinum. Overexpression of RAFTK leads to the activation of p38 MAPK. Furthermore, overexpression of a dominant-negative mutant of RAFTK (RAFTK K-M) inhibits MMS-induced p38 MAPK activation. MKK3 and MKK6 are known potential constituents of p38 MAPK signaling pathway, whereas SEK1 and MEK1 are upstream activators of SAPK/JNK and ERK pathways, respectively. We observe that the dominant-negative mutant of MKK3 but not of MKK6, SEK1, or MEK1 inhibits RAFTK-induced p38 MAPK activity. Furthermore, the results demonstrate that treatment of cells with 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid, tetra(acetoxymethyl)-ester, a membrane-permeable calcium chelator, inhibits MMS-induced activation of RAFTK and p38 MAPK. Taken together, these findings indicate that RAFTK represents a stress-sensitive mediator of the p38 MAPK signaling pathway in response to certain cytotoxic agents.
Footnotes
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↵* This investigation was supported by Public Health Service Grants CA75216 (to S. K.), CA65861 (to R. J. D.) awarded by NCI, and by RO1 HL55445 (to S. A.) from National Institutes of Health.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵‖ To whom correspondence should be addressed: Dept. of Adult Oncology, Dana-Farber Cancer Institute, Harvard Medical School, 44 Binney St., Boston, MA 02115. Tel.: 617-632-2938; Fax: 617-632-2934; E-mail: surender_kharbanda{at}dfci.harvard.edu.
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↵1 MAPK, mitogen-activated protein kinase; JNK/SAPK, c-Jun N-terminal kinase/stress-activated protein kinase; RAFTK, related adhesion focal tyrosine kinase; CADTK, calcium-dependent tyrosine kinase; IR, ionizing radiation; CDDP, cis-platinum; MMS, methylmethane sulfonate; UV, ultraviolet radiation; anti-P-Tyr, anti-phosphotyrosine; BAPTA-AM, 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid, tetra(acetoxymethyl)-ester; Gy, gray; HA, hemagglutinin; GST, glutathione S-transferase; PAGE, polyacrylamide gel electrophoresis ERK, extracellular regulated kinase.
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- Received November 23, 1998.
- Revision received February 5, 1999.
- The American Society for Biochemistry and Molecular Biology, Inc.
