Phosphoisoprenoids Modulate Association of Rab Geranylgeranyltransferase with REP-1

Thoma N.H., Iakovenko A., Goody R.S. and Alexandrov K. (2001) Phosphoisoprenoids Modulate Association of Rab Geranylgeranyltransferase with REP-1. Journal of Biological Chemistry, 276 52: 48637-48643. doi:10.1074/jbc.M108241200

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Author Thoma N.H.
Iakovenko A.
Goody R.S.
Alexandrov K.
Title Phosphoisoprenoids Modulate Association of Rab Geranylgeranyltransferase with REP-1
Journal name Journal of Biological Chemistry   Check publisher's open access policy
ISSN 0021-9258
Publication date 2001-12-28
Year available 2001
Sub-type Article (original research)
DOI 10.1074/jbc.M108241200
Open Access Status File (Publisher version)
Volume 276
Issue 52
Start page 48637
End page 48643
Total pages 7
Place of publication BETHESDA
Language eng
Subject 1303 Specialist Studies in Education
Abstract Rab geranylgeranyltransferase (RabGGTase or GGTase-II) catalyzes the post-translational prenylation of Rab proteins. Rab proteins are recognized as substrates only when they are complexed to Rab Escort Protein (REP). The classical model of prenylation complex assembly assumes initial formation of the Rab.REP binary complex, which subsequently binds to RabGGTase loaded with the isoprenoid donor geranylgeranyl pyrophosphate (GGpp). We demonstrate here that REP-1 can also associate with RabGGTase in the absence of Rab protein and that this interaction is dramatically strengthened by the presence of phosphoisoprenoids such as GGpp. The GGpp-dependent interaction between RabGGTase and REP-1 was observed using affinity precipitations and gel filtration and was quantitated on the basis of fluorescence assays. In the presence of GGpp, REP-1 binds to RabGGTase with a K(d) value of similar to10 nM, while in its absence the affinity between the two proteins is in the micromolar range. We further demonstrate that binding of Rab7 to the RabGGTase.GGpp.REP-1 complex occurs without prior dissociation of REP-1. Analysis of binding and prenylation rate constants indicate that the RabGGTase.GGpp.REP-1 complex can function as a kinetically competent intermediate of the prenylation reaction. We conclude that, depending on the prevailing concentrations, binding of REP-1 to RabGGTase in the presence of GGpp may serve as an alternative pathway for the assembly of the prenylation machinery in vivo. Implications of these findings for the role of REP-1 in the prenylation reaction are discussed.
Keyword Biochemistry & Molecular Biology
Biochemistry & Molecular Biology
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
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Citation counts: TR Web of Science Citation Count  Cited 25 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 28 times in Scopus Article | Citations
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