May play a role in terminally differentiated neurons. Has a Ser/Thr-phosphorylating activity for histone H1. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Found in a complex containing CABLES1, CDK16 and TDRD7. Interacts with TDRD7. Brain specific. Within the brain it is concentrated in the neuronal layers of the hippocampus and olfactory bulb, which mostly consist of post-mitotic neurons. Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. CDC2/CDKX subfamily.