Inactivation of Protein-tyrosine Phosphatases as Mechanism of UV-induced Signal Transduction

doi:10.1074/jbc.274.37.26378

Inactivation of Protein-tyrosine Phosphatases as Mechanism of UV-induced Signal Transduction*

From the ^‡Research Unit “Molecular Cell Biology,” Klinikum der Friedrich Schiller Universität Jena, Drackendorfer Strasse 1, D-07747 Jena, Germany, the ^§Forschungszentrum Karlsruhe, Institute for Genetics, H.v.Helmholtz-Platz, D-76344 Eggenstein Leopoldshafen, Germany, the ^¶Max Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, D-13125 Berlin, Germany, and the ^‖Innovationskolleg Zellspezialisierung, Martin-Luther-Universität Halle/Wittenberg, Hoher Weg 8, 06120 Halle, Germany

Abstract

UV irradiation of cells causes ligand-independent activation of receptor tyrosine kinases. On the basis of dephosphorylation kinetics, UV-induced inactivation of receptor-directed tyrosine phosphatases (PTP) has been proposed as the mechanism of receptor activation (Knebel, A., Rahmsdorf, H. J., Ullrich, A., and Herrlich, P. (1996) EMBO J. 15, 5314–5325). Here we show that four defined protein-tyrosine phosphatases (PTPs), SHP-1, RPTPα, RPTPς, and DEP-1, are partially inactivated upon UV irradiation of PTP-overexpressing cells. The dephosphorylation of coexpressed platelet-derived growth factor β (PDGFβ) receptor by RPTPα is inhibited upon UV irradiation. UV converts RPTPα into a substrate-trapping enzyme which can coprecipitate PDGFβ receptor, similarly to the PTP mutant at the active-center cysteine: C433S. In agreement with the proposed mechanism that inactivation of PTPs accounts for receptor tyrosine kinase activation, no evidence for a UV-induced receptor cross-linking could be obtained in PDGFβ receptor-enriched membrane micelle preparations and in PDGFβ receptor overexpressing 293 cells. The intrinsic activity of PDGFβ receptor kinase was required for the UV-induced enhancement of receptor phosphorylation, but was not changed upon UV irradiation. The data support a mechanism of UV-induced signal transduction involving inactivation of PTPs through an unknown reactive intermediate that oxidizes the conserved cysteine in the active sites of PTPs.

Footnotes

↵* The work was supported by Deutsche Forschungsgemeinschaft Grant SFB344, YE1 (to M. G.), the Max-Planck Society (to F. D. B.), Deutsche Forschungsgemeinschaft Grant RA 247/6-2 and European Community Grant FI4P-CT96-0052 (to P. H.)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.
↵** To whom correspondence should be addressed: Research Unit “Molecular Cell Biology,” Medical Faculty, Friedrich Schiller University, Drackendorfer Str. 1, D-07747 Jena, Germany. Tel.: 49-3641-304-468; Fax: 49-3641-304-462; E-mail: i5frbo@rz.uni-jena.de.
↵2 T. Tenev, S. A. Böhmer, R. Kaufmann, S. Frese, T. Bittorf, T. Beckers, and F. O. Böhmer, submitted for publication.
↵3 S. Groß, A. Knebel, T. Tenev, A. Neininger, M. Gaestel, P. Herrlich, and F. D. Böhmer, unpublished data.
↵4 S. Groß, K. Denner, S. A. Böhmer, and F. O. Böhmer, unpublished data.
↵5 A. Knebel, F. Zaucke, M. Göttlicher, D. Wilhelm, F. D. Böhmer, H. J. Rachmsdorf, H. Krug, and P. Herrlich, unpublished data.
Abbreviations:

UV

ultraviolet

EGF

epidermal growth factor

EGFR

EGF receptor

NAC

N-acetylcysteine

PBS

phosphate-buffered saline

PDGFR

platelet-derived growth factor receptor

PTP

protein tyrosine phosphatase

SH2

Src homology domain 2

VSV

vesicular stomatitis virus

PAGE

polyacrylamide gel electrophoresis

MES

4-morpholineethanesulfonic acid

MAPKAP

mitogen-activated protein kinase-activated protein
- Received November 25, 1998.
- Revision received June 22, 1999.
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