TY - JOUR
T1 - Two Novel GPCR-Type G Proteins Are Abscisic Acid Receptors in Arabidopsis
AU - Pandey, Sona
AU - Nelson, David C.
AU - Assmann, Sarah M.
N1 - Funding Information:
Single gtg1-1 and gtg2-1 mutants were isolated and the gtg1 gtg2 mutant created by D.C.N. in the laboratory of Professor Michael R. Sussman at the University of Wisconsin-Madison, under the support of funds from the UW College of Agricultural and Life Sciences, the Morgridge family, and an NIH Graduate Fellowship Training Grant administered through the Department of Genetics. Other research was performed at Penn State and supported by NSF grant 0209694 and the Penn State Waller Professorship to S.M.A. Technical assistance from Ms. Liza A. Wilson, Ms. Anne Gibson, and Ms. Heather Burch, the pGW series of binary vectors from Dr. Tsuyoshi Nakagawa, modified pEarleyGate 102 vector from Dr. Gabriele Monshausen, advice on phylogenetic analysis from Professor Claude dePamphilis, and access to the FLx800 from Professor Doug Cavener are gratefully acknowledged. D.C.N. isolated the single gtg1-1 and gtg2-1 mutants and created the gtg1 gtg2 double mutant. S.P. and D.C.N. performed initial phenotypic analyses. S.P. and S.M.A. designed, performed, and interpreted all other experiments. S.P. and S.M.A. wrote the paper, with input from all authors.
PY - 2009/1/9
Y1 - 2009/1/9
N2 - In plants, G proteins modulate signaling by the stress hormone, abscisic acid (ABA). We identify and characterize two novel Arabidopsis proteins that show homology to an orphan vertebrate GPCR (GPR89) and interact with the sole Arabidopsis G protein α subunit, GPA1, but also have intrinsic GTP-binding and GTPase activity. We have named these proteins GPCR-type G proteins (GTG1 and GTG2). Arabidopsis mutants lacking both GTG1 and GTG2 exhibit ABA hyposensitivity. GTG1 and GTG2 bind ABA specifically. The GDP-bound form of the GTGs exhibits greater ABA binding than the GTP-bound form, the GTPase activity of the GTGs is inhibited by GPA1, and gpa1 null mutants exhibit ABA-hypersensitive phenotypes. These results predict that, unusually, it is the GDP-bound, not the GTP-bound, form of the GTGs that actively relays the signal. We propose that GTG proteins function both as a new type of G protein and as a class of membrane-localized ABA receptors.
AB - In plants, G proteins modulate signaling by the stress hormone, abscisic acid (ABA). We identify and characterize two novel Arabidopsis proteins that show homology to an orphan vertebrate GPCR (GPR89) and interact with the sole Arabidopsis G protein α subunit, GPA1, but also have intrinsic GTP-binding and GTPase activity. We have named these proteins GPCR-type G proteins (GTG1 and GTG2). Arabidopsis mutants lacking both GTG1 and GTG2 exhibit ABA hyposensitivity. GTG1 and GTG2 bind ABA specifically. The GDP-bound form of the GTGs exhibits greater ABA binding than the GTP-bound form, the GTPase activity of the GTGs is inhibited by GPA1, and gpa1 null mutants exhibit ABA-hypersensitive phenotypes. These results predict that, unusually, it is the GDP-bound, not the GTP-bound, form of the GTGs that actively relays the signal. We propose that GTG proteins function both as a new type of G protein and as a class of membrane-localized ABA receptors.
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U2 - 10.1016/j.cell.2008.12.026
DO - 10.1016/j.cell.2008.12.026
M3 - Article
C2 - 19135895
AN - SCOPUS:58149090404
SN - 0092-8674
VL - 136
SP - 136
EP - 148
JO - Cell
JF - Cell
IS - 1
ER -