Plant heterotrimeric G protein beta subunit is associated with membranes via protein interactions involving coiled-coil formation.
Gbeta subunits from animals are anchored to membranes via Ggamma subunits. No Ggamma has been identified in plants to date. Using differential centrifugation of Arabidopsis and broccoli extracts, Gbeta was highly enriched in the microsomal pellet. Treatment of microsomes with detergents and salts indicates that plant Gbeta is located at the membrane surface and attached to membranes by hydrophobic interactions. Analysis of transgenic plants expressing Gbeta-GFP fusion proteins showed that mutations in the heptad repeat domain of Gbeta severely diminished their membrane association. We propose that plant Gbeta is anchored to membranes by an unknown protein similar to animal Gbeta by Ggamma, via coiled-coil formation.
Institut für Biologie II, Zellbiologie, Universität Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany.
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D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D001937:Brassica / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins; D020962:Heterotrimeric GTP-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008164:Luminescent Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008566:Membranes / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D017434:Protein Structure, Tertiary / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid; D017386:Sequence Homology, Amino Acid; D012995:Solubility; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism
D008164:Luminescent Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D020962:Heterotrimeric GTP-Binding Proteins