Characterization of Heterotrimeric G Protein ?4 Subunit in Rice.

ABSTRACT: Heterotrimeric G proteins are the molecule switch that transmits information from external signals to intracellular target proteins in mammals and yeast cells. In higher plants, heterotrimeric G proteins regulate plant architecture. Rice harbors one canonical ? subunit gene (RGA1), four extra-large GTP-binding protein genes (XLGs), one canonical ?-subunit gene (RGB1), and five ?-subunit genes (tentatively designated RGG1, RGG2, RGG3/GS3/Mi/OsGGC1, RGG4/DEP1/DN1/qPE9-1/OsGGC3, and RGG5/OsGGC2) as components of the heterotrimeric G protein complex. Among the five ?-subunit genes, RGG1 encodes the canonical ?-subunit, RGG2 encodes a plant-specific type of ?-subunit with additional amino acid residues at the N-terminus, and the remaining three ?-subunit genes encode atypical ?-subunits with cysteine-rich C-termini. We characterized the RGG4/DEP1/DN1/qPE9-1/OsGGC3 gene product G?4 in the wild type (WT) and truncated protein G?4?Cys in the RGG4/DEP1/DN1/qPE9-1/OsGGC3 mutant, Dn1-1, as littele information regarding the native G?4 and G?4?Cys proteins is currently available. Based on liquid chromatography-tandem mass spectrometry analysis, immunoprecipitated G?4 candidates were confirmed as actual G?4. Similar to ?-(G?) and ?-subunits (G?), G?4 was enriched in the plasma membrane fraction and accumulated in the developing leaf sheath. As RGG4/DEP1/DN1/qPE9-1/OsGGC3 mutants exhibited dwarfism, tissues that accumulated G?4 corresponded to the abnormal tissues observed in RGG4/DEP1/DN1/qPE9-1/OsGGC3 mutants.

SUBMITTER: Matsuta S 

PROVIDER: S-EPMC6274817 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature