Farnesol is utilized for isoprenoid biosynthesis in plant cells via farnesyl pyrophosphate formed by successive monophosphorylation reactions

• DOI: 10.1073/pnas.96.23.13080
• Publication Date: 2002-07-26T14:35:07Z
• Authors: Long Thai; Jeffrey S. Rush; Jude E. Maul; Timothy Devarenne; Dana L. Rodgers; Joseph Chappell; Charles J. Waechter
• Keywords: Geranylgeraniol; Farnesyl pyrophosphate; Geranylgeranyl pyrophosphate; Isopentenyl pyrophosphate; Isoprene; Farnesyl-diphosphate farnesyltransferase

The ability of Nicotiana tabacum cell cultures to utilize farnesol (F-OH) for sterol and sesquiterpene biosynthesis was investigated. [ 3 H]F-OH readily incorporated into sterols by rapidly growing cultures. However, the incorporation rate reduced greater than 70% in elicitor-treated whereas a substantial proportion radioactivity redirected capsidiol, an extracellular phytoalexin. inhibited squalestatin 1, suggesting that via farnesyl pyrophosphate (F-P-P). Consistent with this possibility, N. proteins were metabolically labeled or H]geranylgeraniol ([ H]GG-OH). Kinase activities converting F-OH monophosphate (F-P) and, subsequently, F-P-P demonstrated directly vitro enzymatic studies. H]F-P H]F-P-P synthesized when exogenous incubated microsomal fractions CTP. kinetics formation suggested precursor–product relationship between H]F-P-P. In agreement kinetic pattern labeling, 32 P]F-P P]F-P-P F-P, respectively, [γ- P]CTP serving as phosphoryl donor. Under similar conditions, catalyzed conversion H]GG-OH H]geranylgeranyl H]GG-P-P) CTP-dependent reactions. A novel biosynthetic mechanism involving two successive monophosphorylation reactions supported observation H]CTP formed microsomes H]CDP either GG-P-P, but not F-P. These results document presence at least CTP-mediated kinases provide utilization GG-OH isoprenoid lipids protein isoprenylation.