RAB6B is a member of the Rab subfamily of small GTPases that regulates intracellular membrane trafficking, specifically functioning in retrograde transport from the Golgi apparatus toward the endoplasmic reticulum 1. Unlike the ubiquitously expressed RAB6A, RAB6B exhibits tissue-specific expression patterns, being predominantly expressed in brain tissue, particularly in microglia, pericytes, and Purkinje cells 1. The protein localizes to the Golgi apparatus and ERGIC-53-positive vesicles, where it maintains Golgi morphology and facilitates retrograde membrane traffic 1. RAB6B plays crucial roles in neuronal development, specifically in neuron projection development and maintaining neuroepithelial integrity through a RAB6-dynein-LIS1 complex that transports apical determinants like Crumbs3 to prevent neural progenitor cell delamination 2. The protein functions as a molecular switch, cycling between active GTP-bound and inactive GDP-bound states, with structural changes in switch regions determining effector specificity 3. RAB6B has emerged as a therapeutic target in cancer, where its expression affects cell proliferation through AKT/JNK signaling pathways 4 and is regulated by microRNAs that control neural stem cell proliferation 5. Additionally, RAB6B expression is associated with drug resistance mechanisms in melanoma through effects on protein prenylation and integrin signaling 6.