Utilization of geranylgeraniol for protein isoprenylation in C6 glial cells.
When rat C6 glial cells were incubated with [3H]geranylgeraniol (GGol), radioactivity was incorporated into a delipidated protein fraction. SDS-PAGE analysis of the protein fraction labeled by [3H]GGol revealed a 46 kDa polypeptide and a group of labeled polypeptides (19-27 kDa) in the same size range as the small GTP-binding proteins. A similar pattern of labeled polypeptides was seen when C6 cells were metabolically labeled with [14C]mevalonolactone. An isotopically labeled product, chromatographically identical to geranylgeranylcysteine (GG-Cys), was released by Pronase E digestion of the [3H]GGol-labeled protein. When the protein fraction from cells metabolically labeled with [3H]mevalonolactone was digested with Pronase E, two radiolabeled products were released with the chromatographic mobilities of farnesyl-cysteine (F-Cys) and GG-Cys. These studies suggest that C6 glial cells are capable of converting GGol to geranylgeranyl pyrophosphate (GG-P-P), or perhaps a novel "activated" form of the allylic isoprenol, that can be utilized for protein isoprenylation reactions.
Crick
D C
DC
Department of Biochemistry, University of Kentucky College of Medicine, Lexington 40536.
Waechter
C J
CJ
Andres
D A
DA
D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D004224:Diterpenes / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism*; D017368:Protein Prenylation; D051381:Rats
D004224:Diterpenes; D009419:Nerve Tissue Proteins; C017338:geranylgeraniol