A Golgi-localized hexose transporter is involved in heterotrimeric G protein-mediated early development in Arabidopsis.
Signal transduction involving heterotrimeric G proteins is universal among fungi, animals, and plants. In plants and fungi, the best understood function for the G protein complex is its modulation of cell proliferation and one of several important signals that are known to modulate the rate at which these cells proliferate is D-glucose. Arabidopsis thaliana seedlings lacking the beta subunit (AGB1) of the G protein complex have altered cell division in the hypocotyl and are D-glucose hypersensitive. With the aim to discover new elements in G protein signaling, we screened for gain-of-function suppressors of altered cell proliferation during early development in the agb1-2 mutant background. One agb1-2-dependent suppressor, designated sgb1-1(D) for suppressor of G protein beta1 (agb1-2), restored to wild type the altered cell division in the hypocotyl and sugar hypersensitivity of the agb1-2 mutant. Consistent with AGB1 localization, SGB1 is found at the highest steady-state level in tissues with active cell division, and this level increases in hypocotyls when grown on D-glucose and sucrose. SGB1 is shown here to be a Golgi-localized hexose transporter and acts genetically with AGB1 in early seedling development.
Wang
Helen X
HX
Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280, USA.
Weerasinghe
Ravisha R
RR
Perdue
Tony D
TD
Cakmakci
Nihal G
NG
Taylor
J Philip
JP
Marzluff
William F
WF
Jones
Alan M
AM
D000483:Alleles; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D001692:Biological Transport; D002455:Cell Division; D049109:Cell Proliferation; D044387:GTP-Binding Protein beta Subunits / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D005947:Glucose / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism*; D020962:Heterotrimeric GTP-Binding Proteins / Q000502:physiology*; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D010802:Phylogeny; D018749:RNA, Plant / Q000378:metabolism*; D015398:Signal Transduction
C089590:AGB1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D044387:GTP-Binding Protein beta Subunits; D009004:Monosaccharide Transport Proteins; D018749:RNA, Plant; C516473:SGB1 protein, Arabidopsis; D020962:Heterotrimeric GTP-Binding Proteins; D005947:Glucose