RAB38 is a small GTPase that functions as a key regulator of intracellular membrane trafficking in specialized cell types, particularly melanocytes, alveolar type II cells, and platelets 1. RAB38 primarily regulates the biogenesis and trafficking of lysosome-related organelles (LROs), including melanosomes, lamellar bodies, and platelet dense granules 12. The protein works cooperatively with RAB32 and the BLOC-3 complex (its guanine nucleotide exchange factor) to redirect trafficking machinery—including AP-1, AP-2, and AP-3 adaptor complexes—to ensure proper sorting and localization of melanogenic enzymes like TYRP1, TYR, and DCT/TYRP2 to melanosomes 2. Additionally, RAB38 plays roles in phagosome maturation during pathogen defense and regulates autophagosomal component recycling through SNX16 interactions 34. Recently, RAB38 was identified as a physiologic regulator of LRRK2, the Parkinson's disease-associated kinase, by mediating its membrane recruitment and substrate phosphorylation in melanocytes 5. Clinically, RAB38 dysfunction is implicated in Hermansky-Pudlak syndrome (HPS), characterized by oculocutaneous albinism, platelet storage defects, and progressive interstitial pneumonia 16. Genome-wide association studies have also identified RAB38 variants as genetic risk factors for hypertension-induced kidney disease and end-stage renal disease 7.