Dual specificity protein kinase activity catalyzing autophosphorylation and phosphorylation of exogenous substrates on both serine/threonine and tyrosine residues. Phosphorylates cofilin at 'Ser-3'. May play an important role in spermatogenesis. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Activated by autophosphorylation on Ser-219. Experimental confirmation may be lacking for some isoforms. Predominantly expressed in testis and prostate. Found predominantly in non-germinal Sertoli cells. Belongs to the protein kinase superfamily. TKL Ser/Thr protein kinase family.