TBC1 domain family member 20

Normal function

The TBC1D20 gene provides instructions for making a protein that helps regulate the activity of other proteins called GTPases, which control a variety of functions in cells. Often referred to as molecular switches, GTPases can be turned on and off. They are turned on (active) when they are attached (bound) to a molecule called GTP and are turned off (inactive) when they are bound to another molecule called GDP. The TBC1D20 protein turns off a GTPase known as RAB18 by stimulating a reaction that turns the attached GTP into GDP. When active, RAB18 is involved in a process called vesicle trafficking, which moves proteins and other molecules within cells in sac-like structures called vesicles. RAB18 regulates the movement of substances between compartments in cells and the storage and release of fats (lipids) by structures called lipid droplets. The protein also appears to play a role in a process called autophagy, which helps clear unneeded materials from cells. RAB18 is important for the organisation of a cell structure called the endoplasmic reticulum, which is involved in protein processing and transport.

The TBC1D20 protein is also thought to inactivate another GTPase called RAB1. RAB1 is important for maintaining the structure of a cell compartment called the Golgi apparatus, in which newly produced proteins are modified so they can carry out their functions. The TBC1D20 protein also appears to play a role in the copying (replication) of viruses in infected cells.

Conditions referring to this gene or chromosome

• Coloboma

• RAB18 deficiency

Other names

C20orf140

dJ852M4.2

WARBM4