protein geranylgeranyltransferase activity Rab geranylgeranyltransferase activity https://github.com/geneontology/go-ontology/issues/25798 https://github.com/geneontology/go-ontology/issues/28526 geranylgeranyl-diphosphate,geranylgeranyl-diphosphate:protein-cysteine geranyltransferase activity molecular_function Catalysis of the reaction: 2 geranylgeranyl diphosphate + protein-cysteine = 2 S-geranylgeranyl-protein + 2 diphosphate. This reaction is the formation of two thioether linkages between the C-1 atom of the geranylgeranyl groups and two cysteine residues within the terminal sequence motifs XXCC, XCXC or CCXX. Known substrates include Ras-related GTPases of a single family and the Rab family. GGTaseII activity MetaCyc:RXN-19996 MetaCyc:RXN-19995 RabGGTase activity type II protein geranyl-geranyltransferase activity MetaCyc:RXN-19997 GGTase-II activity Rab-protein geranylgeranyltransferase activity protein geranylgeranyltransferase type II activity EC:2.5.1.60 GO:0004663