May play a role in chromatin regulation of male germ cells. Interacts (via C-terminus) with CSNK2A2. Present in nuclei of spermatids during chromatin condensation. Expressed exclusively in testis (at protein level). Within testis, expressed mainly in the intermediate compartment of the seminiferous tubules with weaker expression in the basal and adluminal compartments. Phosphorylated by CK2 (casein kinase II), specifically by complexes containing catalytic subunit CSNK2A2. Truncated N-terminus. Truncated N-terminus.