Dlk/ZIP kinase, a novel Ser/Thr-specific protein kinase with multiple functions

Dlk/ZIP kinase is a member of the DAP kinase family which has been implicated in apoptosis. However, Dlk/ZIP kinase does not induce apoptosis per se. Rather, downregulation of Dlk/ZIP kinase by siRNA results in apoptosis and multinucleated cells suggesting that Dlk/ZIP kinase fulfills a vital function in processes other than apoptosis. Indeed, Dlk/ZIP kinase interacts with several transcription and splicing factors pointing to a role in transcription, presumably via chromatin modification. Moreover, it appears to participate in regulation of cell polarity and contractile processes in non-muscle or smooth muscle cells. Finally, Dlk/ZIP kinase seems to play a role in mitosis, particularly cytokinesis. Thus, rather than being a proapoptotic kinase, Dlk/ZIP kinase participates in diverse and vital processes.