Protein unc-13 homolog D (Unc13d)

Plays a role in cytotoxic granule exocytosis in lymphocytes. Required for both granule maturation and granule docking and priming in the immunologic synapse.

Regulates assembly of recycling and late endosomal structures, causing the formation of an endosomal exocytic compartment which fuses with perforin-containing granules in the immunologic synapse and licences them for exocytosis (By similarity). Regulates Ca(2+)- dependent secretory lysosome exocytosis in mast cells.