Protein unc-13 homolog D
The UNC13D gene at 17q25.1 codes for the 1090 amino acid protein unc-13 homolog D. This protein is required for both granule maturation and granule docking and priming at the immunologic synapse. It regulates assembly of recycling and late endosomal structures, allowing the formation of an endosomal exocytic compartment that fuses with perforin-containing granules at the immunologic synapse and permits their exocytosis. In mast cells the process is calcium dependent. Three isoforms are known.
Mutations are associated with familial haemophagocytic lymphohistiocytosis type 3.