RAB gene family

Genes in the RAB family provide instructions for making proteins that are involved in a process called vesicle trafficking, which moves materials within cells in sac-like structures called vesicles. Some vesicles are formed when the cell membrane folds around a substance outside the cell. The vesicle is drawn into the cell and is pinched off from the cell membrane. This method of bringing substances into cells is called endocytosis.

Vesicles may also be formed from the membranes of other structures within the cell, such as the endoplasmic reticulum or the Golgi apparatus. Vesicles transport many types of molecules from the interior of the cell to its surface, where they may attach and interact with other substances, or be secreted by the cell.

RAB proteins are GTPases, which means they convert a molecule called GTP into another molecule called GDP. The RAB protein acts like a switch, and it is turned on and off by GTP and GDP molecules. The protein must be turned on (activated) by attaching (binding) to GTP, and it is turned off (inactivated) when it converts GTP to GDP. Only the active protein can bind to other proteins called Rab effectors, which help move vesicles to their proper destination. This switching function helps regulate vesicle trafficking in the nervous system and other tissues.