Fig. 1. CrkRS is a novel CDK-related protein kinase. (A) Nucleotide and predicted amino acid sequences of the CrkRS cDNA. CrkRS cDNA has an open reading frame of 4473 nucleotides encoding 1490 amino acids. The RS domain is in bold and the kinase domain is underlined. Residues corresponding to the conserved threonine and tyrosine phosphorylation sites of CDK1 are in bold and underlined. A run of nine proline residues is in italics. These sequence data are available from GenBank/EMBL/DDBJ, accession number AF227198. (B) Alignment of the amino^Macid residues encompassing the kinase domains of CHED, CrkRS, and the gene^Mproducts of CG7597 (Drosophila) and B0285 (C. elegans). The^MCHED, CG7597, B0285.1 and B0285.2 sequences were obtained from GenBank^M(accession numbers A38197, AAF51738, CAA84302 and Z34533, respectively). Note,^Mthe C. elegans protein kinase is currently split into two genes in^Mthe database. The RS and proline-rich domain on clone B0285.2 was removed from^Mthe protein kinase domain on clone B0285.1 by the annotators because it did^Mnot resemble any CDKs in the database at that time (R. Durbin, personal^Mcommunication). (C) Schematic diagrams of CrkRS and the gene products of^MCG7597 (Drosophila) and B0285 (C. elegans). Bipartite^Mnuclear localisation sequences (NLS) are indicated by arrows, RS domains by^Mblack rectangles, kinase domains by grey rectangles, PEST regions by triangles^Mand SH3-binding domains by squares.