CHARACTERIZATION OF THE PROLINE-RICH REGION OF MOUSE MAPKAP KINASE-2 - INFLUENCE ON CATALYTIC PROPERTIES AND BINDING TO THE C-ABL SH3 DOMAIN IN-VITRO

The primary structure of mouse MAP kinase-activated protein (MAPKAP) k inase 2 contains a proline-rich N-terminal region which might Function as a src-homology 3 (SH3) domain-binding motif in vivo. To demonstrat e the ability of this region to bind SH3 domains, we analyzed the inte raction of the SH3 domain of the protein tyrosine kinase c-abl with MA PKAP kinase 2. It is demonstrated, that the proline-rich region specif ically binds c-abl-SH3 domain in vitro. Furthermore, it is shown, that deletion of this proline-rich region does not significantly influence the substrate binding properties of the enzyme when analyzed with the substrate small heat shock protein Hsp25. The data suggest that the p roline-rich region of MAPKAP kinase 2 could interact with proteins con taining SH3-domains also in vivo regulating its cellular localization and/or modulating its enzymatic properties. (C) 1994 Academic Press, I nc.