Required for sperm production and function. Plays a role in DNA condensation during postmeiotic chromatin remodeling (By similarity). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with HSP90; this interaction stabilizes and activates TSSK6 (By similarity). Interacts with the heat shock proteins HSPCB, HSPA8 and HSPA1A. These interactions appear to be required for TSSK6 kinase activity. Interacts with TSACC; this interaction is direct and recruits TSACC to HSP90, which is essential for kinase activity. Highly expressed in testis. Expressed at lower levels in colon, small intestine, ovary, prostate, thymus, spleen and peripheral blood leukocytes. Autophosphorylated. Ubiquitinated; HSP90 activity negatively regulates ubiquitination and degradation. Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family.