RAB44 is a large Rab GTPase that regulates intracellular membrane trafficking and vesicle dynamics. The protein contains an N-terminal EF-hand domain, a coiled-coil domain, and a C-terminal Rab GTPase domain 1. RAB44 promotes mast cell degranulation upon IgE Fc receptor-mediated activation by regulating lysosomal exocytosis 2. The protein exists as multiple isoforms that exhibit differential subcellular localization - long isoforms localize mainly to lysosomes while short isoforms localize to the endoplasmic reticulum 2. RAB44 mechanistically interacts with VAMP8, a v-SNARE protein involved in vesicle fusion 2. The EF-hand domain is required for calcium-induced translocation to the plasma membrane, while the coiled-coil domain is important for proper localization and organelle formation 1. RAB44 plays significant roles in inflammatory diseases, as RAB44-deficient mice show reduced inflammation and bone destruction in collagen antibody-induced arthritis 3. The gene is also implicated in atopic dermatitis treatment response and serves as a biomarker for therapeutic efficacy 4. Additionally, RAB44 variants have been identified in familial and sporadic meningiomas, suggesting potential roles in cancer predisposition 5.