Exploring the specificity of prenyl protein-specific methyltransferase with synthetic prenylated rab peptides

✍ Scribed by Michael H. Gelb; Yuval Reiss; Farideh Ghomashchi; Christopher C. Farnsworth

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 317 KB
• Volume: 5
• Category: Article
• ISSN: 0960-894X
• DOI: 10.1016/0960-894x(95)00134-f

✦ Synopsis

Most Rab proteins contain two C-terminal geranylgeranyl groups. Some members are Cterminally methylated, whereas others are not. Synthetic peptides bearing the sequence of the C-termini of Rab proteins and containing the C-terminal motif C(S-geranylgeranyl)AC(S-geranylgeranyl) are substrates for the membrane-bound prenyl protein-specific methyltransferase, whereas those that end in C(Sgeranylgeranyl)C(S-geranylgeranyl) are not.

Rab proteins are 21 to 25-kDa GTP-binding proteins that play a role in intracellular vesicle trafficking and cellular secretion. 1 Most, and perhaps all, Rab proteins contain covalently attached geranylgeranyl groups at their C-termini, and some are methylated at their C-termini. 2-6 As a first step toward the understanding of the role of posttranslational modifications in supporting rab functions, it is necessary to fully characterize the structure of these modifications and to understand the enzymatic pathways that gives rise to them. Unlike proteins such as the -y-subunits of heterotrimeric G proteins which contain a single C-terminal geranylgeranyl group on the cysteine in the sequence CXXX, 7, 8 some Rab p,'oteins, such as Rab 3a, contain a C-terminal