Abstract
Different lines of evidence suggest that specific events during the cell cycle may be mediated by a heterotrimeric G-protein activated by a cognate G-protein coupled receptor. However, coupling between the only known Galpha-subunit of the heterotrimeric G-protein (GPA1) and the only putative G-protein coupled receptor (GCR1) of plants has never been shown. Using a variety of approaches, we show here that GCR1-enhanced thymidine incorporation into DNA depends on an increase in phosphatidylinositol-specific phospholipase C activity and an elevation of inositol 1,4,5-trisphosphate levels in the cells. Tobacco (Nicotiana tabacum) cells that overexpress either Arabidopsis GCR1 or GPA1 display this phenomenon. We suggest on the basis of these results that GCR1-controlled events during the cell cycle involve phosphatidylinositol-specific phospholipase C as an effector of GCR1 and inositol 1,4,5-trisphosphate as a second messenger, and that GCR1 and GPA1 are both involved in this particular signaling pathway.
MeSH terms
-
Arabidopsis Proteins / metabolism*
-
Cloning, Molecular
-
DNA Replication / genetics*
-
DNA, Plant / biosynthesis
-
Enzyme Activation
-
Enzyme Inhibitors / pharmacology
-
Estrenes / pharmacology
-
Inositol 1,4,5-Trisphosphate / metabolism
-
Models, Biological
-
Nicotiana / metabolism
-
Phosphatidylinositol Diacylglycerol-Lyase / antagonists & inhibitors
-
Phosphatidylinositol Diacylglycerol-Lyase / metabolism*
-
Phosphoinositide Phospholipase C
-
Phosphorylation
-
Protein Kinase C / metabolism
-
Pyrrolidinones / pharmacology
-
Receptors, G-Protein-Coupled / metabolism*
-
Recombinant Proteins / metabolism
-
Signal Transduction
-
Thymidine / metabolism
-
Transcription Factors / metabolism
Substances
-
Arabidopsis Proteins
-
DNA, Plant
-
Enzyme Inhibitors
-
Estrenes
-
GCR1 protein, Arabidopsis
-
Pyrrolidinones
-
Receptors, G-Protein-Coupled
-
Recombinant Proteins
-
Transcription Factors
-
1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione
-
Inositol 1,4,5-Trisphosphate
-
Protein Kinase C
-
Phosphoinositide Phospholipase C
-
Phosphatidylinositol Diacylglycerol-Lyase
-
Thymidine