Alternatively Spliced Focal Adhesion Kinase in Rat Brain with Increased Autophosphorylation Activity

doi:10.1074/jbc.272.45.28720

Alternatively Spliced Focal Adhesion Kinase in Rat Brain with Increased Autophosphorylation Activity*

From INSERM U 114, Chaire de Neuropharmacologie, Collège de France, 11 place Marcelin Berthelot, 75231 Paris cedex 05, France

Abstract

pp125 focal adhesion kinase (FAK), a cytoplasmic tyrosine kinase transducing signals initiated by integrin engagement and G protein-coupled receptors, is highly expressed in brain. FAK from brain had a higher molecular weight and an increased autophosphorylation activity, than from other tissues. In addition to a 9-base insertion in the 3′-coding region, which defines FAK+, rat striatal FAK mRNAs contained several additional short exons, coding for peptides of 28, 6, and 7 residues, respectively (termed boxes 28, 6, and 7), surrounding the autophosphorylated Tyr-397. In transfected COS 7 cells, the presence of boxes 6 and 7 conferred an increased overall tyrosine phosphorylation, a higher phosphorylation of Tyr-397 assessed with a phosphorylation state-specific antibody, and a more active autophosphorylation in immune precipitates. The presence of box 28 did not alter further these parameters. Two-dimensional phosphopeptide maps of hippocampal FAK were identical to those of FAK+6,7. The presence of the various exons did not alter the interaction of FAK with c-Src, n-Src, or Fyn. Thus, several splice isoforms of FAK are preferentially expressed in rat brain, some of which have an increased autophosphorylation activity, suggesting that FAK may have specific properties in neurons.

Footnotes

↵* 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.
↵‡ Supported by a fellowship from the European Community under a Human Capital and Mobility contract (ERB CHBG * CT 94 0705). Present address: Dept. de Biologia Ce1·lular Animal i Vegetal, Facultat de Biologia, Universitat de Barcelona, Diagonal, 645 08028 Barcelona, Spain.
↵§ Supported by a European Community contract (ERB CI1 * CT 94 0038).
↵¶ To whom correspondence should be sent. Tel.: 33-1-44-27-12-61; Fax: 33-1-44-27-12-75; E-mail: girault{at}infobiogen.fr.
↵1 The abbreviations used are: FAK, pp125 focal adhesion kinase; DOTAP,N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium me- thylsulfate; PWR, Pro-Trp-Arg; SH2, Src-homology domain 2; SH3, Src-homology domain 3.
↵2 P. Derkinderen, J. C. Sicilians, M. Toutant, and J.-A. Girault, submitted for publication.
↵3 M. Toutant, A. Costa J-M. Studler, M. Gelman, and J-A. Girault, manuscript in preparation.
- Received July 23, 1997.
- Revision received September 4, 1997.