Probable serine/threonine protein kinase. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with Mtor. Found in the cytoplasm during interphase. Localizes to the mitotic spindle in dividing cells. Detected in larval brain. Detected at low levels throughout development. Highest expression levels are seen in embryos. Embryonic lethal. Belongs to the protein kinase superfamily. CK1 Ser/Thr protein kinase family.