Fig. 1. Characterization of the Clik1 kinase. (A) The amino-acid sequence of Clik1, demonstrating the kinase domain (underlined), the EST contig (double underlined), potential nuclear localization signals (dotted boxes) and the conserved lysine residue (asterisk) that was mutated to methionine to generate Myc-K98M. The GenBank Accession number is AF195026. (B) Immunoprecipitates from U2OS cells transfected with Myc-tagged Clik1 (Myc-Clik1) or with an ATP-binding site mutant Myc-tagged Clik1 (Myc-K98M) were subjected to an in vitro kinase reaction followed by SDS-PAGE, transfer to a nitrocellulose membrane and autoradiography (IP-kinase). Subsequently anti-Myc western blot analysis was used to visualize the 46 kDa Myc-Clik1 protein (IP-Western).