Dyrk (Downs Syndrome critical region)

Dyrk, the vertebrate of Drosophilia minibrain, is a dual-specificity kinase predominately expressed in the central nervous system. The human clone has been isolated from the Downs' syndrome critical region and it is potentially implicated in the neuropathology of the disease. Main features of the protein include an N-terminal nuclear translocation signal, a putative leucine zipper domain, a core kinase domain with some similarity to kinases involved in cell cycle regulation and a C-terminal PEST sequence. The Dyrk kinase can be phosphorylated on tyrosine residues, leading to an active kinase that can phosphorylated itself or exogenous substrates on both tyrosine and serine/threonine residues. Dyrk can also multimerize and translocate to the nucleus. Present studies on Dyrk suggest a potential role for this kinase in the exit from the cell cycle and the beginning of neuronal differentiation.