RNA recognition motif (RRM) found in U2AF homology motif kinase 1 (UHMK1) and similar proteins
This subgroup corresponds to the RRM of UHMK1. UHMK1, also termed kinase interacting with stathmin (KIS) or P-CIP2, is a serine/threonine protein kinase functionally related to RNA metabolism and neurite outgrowth. It contains an N-terminal kinase domain and a C-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), with high homology to the corresponding motif of the mammalian U2 small nuclear ribonucleoprotein auxiliary factor U2AF 65 kDa subunit (U2AF65 or U2AF2). UHMK1 targets two key regulators of cell proliferation and migration, the cyclin-dependent kinase (CDK) inhibitor p27Kip1 and the microtubule-destabilizing protein stathmin. It plays a critical role during vascular wound repair by preventing excessive vascular smooth muscle cell (VSMC) migration into the vascular lesion. Moreover, UHMK1 may control cell migration and neurite outgrowth by interacting with and phosphorylating the splicing factor SF1, thereby probably contributing to the control of protein expression. Furthermore, UHMK1 may be functionally related to microtubule dynamics and axon development. It localizes to RNA granules, interacts with three proteins found in RNA granules (KIF3A, NonO, and eEF1A), and further enhances the local translation. UHMK1 is highly expressed in regions of the brain implicated in schizophrenia and may play a role in susceptibility to schizophrenia.