MARK1 (MAP/microtubule affinity-regulating kinase 1) belongs to the MARK family of serine/threonine kinases. MARK family protein kinases phosphorylate microtubule-associated proteins and may play a role in cytoskeletal stability. MARK2 refers to MAP/microtubule affinity-regulating kinase 2 isoform a [Homo sapiens]. EMK (ELKL Motif Kinase) is a small family of ser/thr protein kinases involved in the control of cell polarity, microtubule stability and cancer. Several cDNA clones have been isolated that encoded two isoforms of the human ser/thr protein kinase EMK1 called MARK2. MARK3 was originally identified as a marker that was induced by treatment with DNA damaging agents, and loss of MARK3 was found with carcinogenesis in the pancreas. MARK4 contains an N terminal serine/threonine kinase domain, a central ubiquitin associated domain, and a C terminal KA1 associated kinase domain. RT PCR analysis detects upregulated expression of the gene for MARK4 in nearly all clinical hepatocellular carcinoma cells.
