SNX13 (sorting nexin 13) is a multifunctional protein involved in intracellular trafficking, lipid metabolism regulation, and cellular signaling. The protein contains a PX domain that binds phosphatidylinositol 3-phosphate, localizing SNX13 to early endosomes and endoplasmic reticulum-lysosome membrane contact sites 1 2. SNX13 functions as a negative regulator of lysosomal cholesterol export, and its knockout leads to redistribution of lysosomal cholesterol and accumulation of triacylglycerol-rich lipid droplets 3. In cardiac tissue, SNX13 plays a critical protective role by mediating the endosomal trafficking of apoptosis repressor with caspase recruitment domain (ARC) through its N-terminal PXA structure, preventing cardiomyocyte apoptosis 4. Reduced SNX13 levels are associated with heart failure in both humans and animal models 4. Additionally, SNX13 contains an RH domain that forms homodimers but lacks typical G protein regulatory function, distinguishing it from canonical RGS proteins 5. Genetic variants in SNX13 have been associated with developmental delay and neonatal abstinence syndrome, suggesting broader roles in neurodevelopment 6 7.