Rab GTPases localise to distinct cellular organelles and regulate all stages of intracellular membrane trafficking in eukaryotic cells. Their activity state and functional effects are controlled and or mediated by several interacting proteins, including guanine nucleotide exchange proteins, GTPase Activating proteins, effector and motor proteins. Rab GTPase function is essential for a vast range of normal cellular physiological processes, ranging from Long Term Potentiation (LTP) to cellular uptake of glucose in response to insulin signalling.