May play a role in sperm motility, especially in the regulation of flagellar function. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Encoded on the T-complex, a region of 20-30 Mb on proximal third of mouse chromosome 17. Naturally occurring variant forms of the T-complex, known as complete t-haplotypes, are found in wild mouse populations. The t-haplotypes contain at least four nonoverlapping inversions that suppress recombination with the wild-type chromosome, and lock into strong linkage disequilibrium loci affecting normal transmission of the chromosome, male gametogenesis and embryonic development. Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. Smok subfamily.