Rab11a, Rab11b and Rab25 are members of the Rab11 family of small Ras-like GTPases. Rab11 (isoforms Rab11a and Rab11b) functions as a key regulator in the recycling of perinuclear, plasma membrane and Golgi compartment endosomes. Despite some overlap, distinct differences exist between Rab11a and Rab11b in both their cellular distribution and functional roles. Rab11a is ubiquitously expressed while Rab11b is found mainly in the heart and brain. Like other Rab proteins, Rab11 exerts its function via interactions with Rab11 family interacting proteins (FIPs). While there are three distinct classes of FIPs, all appear to share a conserved carboxy-terminal Rab-binding domain that allows Rab-FIP protein interaction. When bound together, these proteins are thought to regulate membrane-associated protein sorting.