Identification of Heterotrimeric G Protein ?3 Subunit in Rice Plasma Membrane.

ABSTRACT: Heterotrimeric G proteins are important molecules for regulating plant architecture and transmitting external signals to intracellular target proteins in higher plants and mammals. The rice genome contains one canonical ? subunit gene (RGA1), four extra-large GTP-binding protein genes (XLGs), one canonical ? subunit gene (RGB1), and five ? subunit genes (tentatively named RGG1, RGG2, RGG3/GS3/Mi/OsGGC1, RGG4/DEP1/DN1/OsGGC3, and RGG5/OsGGC2). RGG1 encodes the canonical ? subunit; RGG2 encodes the plant-specific type of ? subunit with additional amino acid residues at the N-terminus; and the remaining three ? subunit genes encode the atypical ? subunits with cysteine abundance at the C-terminus. We aimed to identify the RGG3/GS3/Mi/OsGGC1 gene product, G?3, in rice tissues using the anti-G?3 domain antibody. We also analyzed the truncated protein, G?3?Cys, in the RGG3/GS3/Mi/OsGGC1 mutant, Mi, using the anti-G?3 domain antibody. Based on nano-liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, the immunoprecipitated G?3 candidates were confirmed to be G?3. Similar to ? (G?) and ? subunits (G?), G?3 was enriched in the plasma membrane fraction, and accumulated in the flower tissues. As RGG3/GS3/Mi/OsGGC1 mutants show the characteristic phenotype in flowers and consequently in seeds, the tissues that accumulated G?3 corresponded to the abnormal tissues observed in RGG3/GS3/Mi/OsGGC1 mutants.

SUBMITTER: Nishiyama A 

PROVIDER: S-EPMC6274724 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature