DYRK1B

DYRK1B, better known as MIRK (minibrain-related kinase), is a predominantly nuclear member of the DYRK1 branch enriched in skeletal muscle, brain, and testis. It undergoes activation-loop tyrosine autophosphorylation and then phosphorylates serine/threonine substrates connected to cell-cycle withdrawal and differentiation, contributing to p27-mediated quiescence and to myogenic gene programs. MIRK activity is restrained by chaperone complexes and can be induced under stress conditions. Elevated DYRK1B expression has been reported in pancreatic ductal adenocarcinoma, prostate cancer, and other malignancies, where it supports the survival of slowly cycling cells. The recombinant protein is used in differentiation models and oncology inhibitor screens.