Cooperates with Rab11 and fwd/PI4K to mediate the flow of membrane through the Golgi, which is required to support cleavage furrow ingression, therefore promoting cytokinesis in male meiotic cells. May be part of the multisubunit TRAPP (transport protein particle) complex. Specific to spermatocytes. Expressed in embryos and adults of males and females. Failure of both actomyosin ring constriction and furrow ingression in male meiotic cells. Belongs to the NIBP family.