RAB26 is a small GTPase that regulates intracellular membrane trafficking and secretory pathways. As a member of the Rab protein family, RAB26 cycles between inactive GDP-bound and active GTP-bound states to recruit effectors responsible for vesicle formation, movement, and fusion 1. The protein mediates anterograde transport from the Golgi to the plasma membrane and plays critical roles in regulated exocytosis, including secretion of neurotransmitters and digestive enzymes 2. RAB26 is particularly important for unconventional protein secretion: it regulates lysosomal-related organelle exocytosis required for SOD1 secretion in neurons, with implications for amyotrophic lateral sclerosis pathogenesis 2. RAB26 also controls macrophage phagocytosis through MFN2 trafficking to mitochondria, affecting bacterial clearance and inflammatory responses in acute respiratory distress syndrome 3. Additionally, RAB26 maintains endothelial barrier integrity in acute lung injury by promoting autophagy-dependent degradation of phosphorylated SRC and stabilization of VE-cadherin at adherens junctions 4. In cancer biology, RAB26 regulates autophagy and is implicated in chemotherapy resistance: KLF4-mediated RAB26 downregulation sensitizes colon cancer cells to 5-FU 5, and RAB26 operates downstream of NAD+ biosynthesis in non-small cell lung cancer 6. Genetic variation in RAB26's GCC repeat has been associated with late-onset Alzheimer's disease susceptibility 7. Upregulated RAB26 expression correlates with poor prognosis in triple-negative breast cancer 8.