Rab geranylgeranyltransferase subunit beta

Rab geranylgeranyltransferase subunit beta (RABGGTB) forms part of the catalytic core of RabGGTase, a heterodimeric enzyme comprised of alpha and beta subunits. This enzyme is responsible for transferring geranylgeranyl groups to Rab GTPases, which is critical for their association with cellular membranes and, consequently, for regulating vesicular transport processes. The beta subunit contains most of the active site residues, forming an alpha-alpha barrel with a deep prenyl-binding pocket and coordinating catalytic metal ions (Zn²⁺ and Ca²⁺). RabGGTase does not recognize Rab substrates alone but requires Rab escort protein (REP) to present Rab GTPases for prenylation. Unlike type I enzyme, it works broadly on Rab proteins, outsourcing substrate recognition to REP, thereby enabling modification of many different Rab GTPases involved in trafficking, secretion, and possibly disease pathogenesis. Bisphosphonate drugs, used in the treatment of bone diseases, can inhibit RabGGTase, although their effectiveness varies in vivo. If you need details for the alpha subunit or the whole enzyme, those differ but are closely related. The beta subunit specifically refers to the structural and catalytic protein encoded by the *RABGGTB* gene.

Other names

protein geranylgeranyltransferase type II beta subunitRABGGTBGGTase-II beta subunit

Inhibition of RabGGTase prevents geranylgeranylation of Rab proteins, affecting their localization and function (resulting in disruption of vesicular trafficking and osteoclast activity)