Phosphorylation of myosin II regulatory light chain by ZIP kinase is responsible for cleavage furrow ingression during cell division in mammalian cultured cells

•ZIPK is responsible for phosphorylation of MRLC at the contractile ring.•The cytokinetic abnormalities in ZIPK depleted cells were rescued by phosphorylation-mimic MRLC expression.•We revealed that ZIPK regulates cytokinesis through MRLC phosphorylation.

Zipper-interacting protein kinase (ZIPK) is known to regulate several functions such as apoptosis, smooth muscle contraction, and cell migration. While exogenously expressed GFP-ZIPK localizes to the cleavage furrow, role of ZIPK in cytokinesis is obscure. Here, we show that ZIPK is a major MRLC kinase during mitosis. Moreover, ZIPK siRNA-mediated knockdown causes delay of cytokinesis. The delay in cytokinesis of ZIPK-knockdown cells was rescued by the exogenous diphosphorylation-mimicking MRLC mutant. Taken together, these findings suggest that ZIPK plays a role in the progression and completion of cytokinesis through MRLC phosphorylation.