GAK antibody

Background of GAK antibody

he cell cycle of eukaryotes is regulated by cyclins and cyclin-dependent protein kinases (CDKs). Cyclin G1 exhibits closest sequence identity to the cyclin A family. Identification of cyclin G1 as a direct transcriptional target of the p53 tumor suppressor gene product indicates that cyclin G functions downstream of p53. GAK (a cyclin G associated kinase), an association partner of cyclin G1 and CDK5, which is expressed ubiquitously, with the highest level of expression being observed in the testis. The predicted amino acid sequence of GAK possesses an N-terminal Ser/Thr protein kinase catalytic domain with a long C-terminal extension. There are two putative dinucleotide-binding motifs in the kinase domain suggesting that GAK activity is some how modulated by dinucleotides such as ADP or GDP. As GAK lacks PSTAIR motif, it can not be considered a member of the CDK family. Kinase activities of GAK is almost throughout the cell cycle. In the middle part of the molecule, GAK resembles both tensin, an actin-binding component of adhesion plaques (also called focal contacts) and other submembranous cyto skeletal structure, and auxilin, a coat component of brain clathrin-coated vesicles. The domain homologous to tensin and auxilin occupies more than 50% of the whole molecule. A leucine zipper motif, whose physiological meaning is unknown, also located in this domain. A phosphorylation recognition site for a tyrosine kinase is located at position 403-410 (KGDLDISY). One, 19 and 24 potential phosphorylation sites for cAMP-dependent protein kinase, protein kinase C and casein kinase II protein kinase, respectively, are also located through whole mol ecule. The presence of a Ser/Thr kinase domain at the N-terminal portion of the molecule suggests that GAK plays a role as a modulator of signal transduction, by relaying the phosphorylation signal from an unidentified tyrosine kinase to unidentified GAK phosphorylation targets.