Rab geranylgeranyltransferase

REP therefore plays an important role in binding and solubilising the geranylgeranyl groups and delivers the Rab protein to the relevant cell membrane.

Studies of mice have shown that Rab GGTase genes are expressed in all major adult organs, as well as in some embryonic units, including the spinal cord and liver (Chinpaisal).

Rab GGTase is “responsible for the largest number of individual protein prenylation events in the cell,”[1] probably due to this ability to interact with many different Rab proteins (it can prenylate any sequence containing a cysteine residue).

RabGGTase is a heterodimer composed of alpha and beta subunits that are encoded by the RABGGTA and RABGGTB genes, respectively.

The structure of rat RabGGTase has been determined by X-ray diffraction (see image to the left) to a resolution of 1.80 Å.

Crystallographic structure of rat RabGGTase (alpha subunit = green, beta subunit = slate blue, calcium ions are shown as green balls, zinc ion as a blue ball). [ 1 ]