Testis-specific serine/threonine-protein kinase required during spermatid development. Phosphorylates 'Ser-288' of TSKS. Involved in the late stages of spermatogenesis, during the reconstruction of the cytoplasm. During spermatogenesis, required for the transformation of a ring-shaped structure around the base of the flagellum originating from the chromatoid body.
Electrospray Q‐TOF2 mass spectroscopy analysis of a trypsin digested TSSK1 purified from E. coli, revealed that it was phosphorylated at its T‐loop residue (Fig. 2D), indicating that TSSK1 as was previously shown for MELK [18], can autophosphorylate its T‐loop Thr residue.