geranylgeranyltransferase-beta 2 (RABGGTB)

Function

• beta subunit of geranylgeranyltransferase-2
• catalyzes the transfer of a geranyl-geranyl moiety from geranyl-geranyl pyrophosphate to both Cys in Rab proteins with an -XXCC, -XCXC & -CCXX C-terminal, such as RAB1A, RAB3A & RAB5A respectively

geranylgeranyl diphosphate + protein-cysteine
                 <-->
S-geranylgeranyl-protein + diphosphate

Cofactor: binds 1 Zn+2 per subunit (putative)

Structure

• heterodimer of an alpha & a beta subunit, collectively called component B
• interaction of beta subunit with prenylated PTP4A2 precludes its association with subunit alpha, & inhibits enzyme activity
• enzymatic reaction requires the aid of a Rab escort protein (also called component A)
• belongs to the protein prenyltransferase subunit beta family
• contains 6 PFTB repeats

More general terms

• prenyltransferase-beta

Component of

• geranylgeranyltransferase-2 (GGTase-2, rab GGTase)

Database

• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:5876
• OMIM: https://mirror.omim.org/entry/179080
• UniProt: http://www.uniprot.org/uniprot/P53611.html