MAP/Microtubule Affinity Regulating Kinase 3 (MARK3)

CTAK1 was expressed as 3.1- and 3.8-kb transcripts in all human tissues examined; an additional 3.0-kb transcript was observed in heart. The predicted 729-amino acid CTAK1 protein belongs to the AMPK subfamily of protein kinases. Members of this subfamily are characterized by a conserved N-terminal kinase domain, a divergent C-terminal region, and a conserved region of about 40 amino acids at their extreme C-termini, which end with an ELKL (glutamate-leucine-lysine-leucine) domain. CTAK1 protein from HeLa cell lysates resolved as a doublet of approximately 78 and 80 kD in Western blot and immunoprecipitation analyses. Indirect immunofluorescence detected CTAK1 in the cytoplasm but not the nucleus of HeLa cells.