Biochem/physiol Actions

ML167 is the first highly selective inhibitor of of Cdc2-like kinase 4 (Clk4) with an IC₅₀ of 136 nM for Clk4, >10-fold selectivity for closely related kinases Clk1-3 and Dyrk1A/1B, and minimal activity against a panel of other kinases tested. The Cdc2-like kinases (Clk’s) and the dual-specificity tyrosine phosphorylation-regulated kinases (Dyrk’s) are involved in regulation of gene splicing. The Cdc2-like kinases phosphorylate the serine/arginine-rich (SR) proteins, a major component of the spliceosome.