TbG63, a golgin involved in Golgi architecture in Trypanosoma brucei

Golgins are coiled-coil proteins that have been implicated in the structure and function of the Golgi complex. Here, we identify and characterize a trypanosomal golgin, TbG63, showing that it has a C-terminal membrane anchor and an N-terminus that projects into the cytoplasm. TbG63 in procyclic parasites is localized to the Golgi and interacts with the active, GTP-form of TbRab1A. Overexpression of TbG63 has dramatic effects on Golgi architecture - effects that require the N-terminus - whereas depletion has little, if any, effect on the growth rate. By contrast, in the bloodstream form of the parasite, depletion of TbG63 slows growth, although it has no obvious effect on the transport of a variant surface glycoprotein (VSG) or on Golgi structure. TbG63 might be a useful tool to study the structure and functioning of the Golgi complex.