Regulates phosphatase activity of protein phosphatase 1 (PP1) complexes in the testis. Interacts with PPP1CC isoform gamma-2; the interaction is direct. Interacts with actin, dynein, KIF5B, KIFC1 and tubulin. Associates with microtubules. Colocalizes with alpha tubulin to the manchette of developing spermatids. Detected to nuclear rim in pachytene spermatocytes. Detected at nuclear surface, opposite the acrosome in elongating spermatids. Detected at the microtubule- organizing center (MTOC). Localized to the centrosomal region of late-stage spermatids. Testis-specific. Expressed in spermatids (at protein level). Testis-specific. Phosphorylated; during the first round of spermatogenesis with a marginal increase at 21 days after birth.