GTP-binding proteins in plants: new members of an old family.
Regulatory guanine nucleotide-binding proteins (G proteins) have been studied extensively in animal and microbial organisms, and they are divided into the heterotrimeric and the small (monomeric) classes. Heterotrimeric G proteins are known to mediate signal responses in a variety of pathways in animals and simple eukaryotes, while small G proteins perform diverse functions including signal transduction, secretion, and regulation of cytoskeleton. In recent years, biochemical analyses have produced a large amount of information on the presence and possible functions of G proteins in plants. Further, molecular cloning has clearly demonstrated that plants have both heterotrimeric and small G proteins. Although the functions of the plant heterotrimeric G proteins are yet to be determined, expression analysis of an Arabidopsis G alpha protein suggests that it may be involved in the regulation of cell division and differentiation. In contrast to the very few genes cloned thus far that encode heterotrimeric G proteins in plants, a large number of small G proteins have been identified by molecular cloning from various plants. In addition, several plant small G proteins have been shown to be functional homologues of their counterparts in animals and yeasts. Future studies using a number of approaches are likely to yield insights into the role plant G proteins play.
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Cold Spring Harbor Laboratory, NY 11724.
D000818:Animals; D005057:Eukaryotic Cells / Q000502:physiology; D019204:GTP-Binding Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D017343:Genes, Plant / Q000235:genetics*; D006160:Guanosine Triphosphate / Q000378:metabolism; D018521:Plant Physiological Phenomena; D010944:Plants / Q000235:genetics; D030821:Plants, Genetically Modified; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D015003:Yeasts / Q000235:genetics
D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins