Mg. Mason et Jr. Botella, Isolation of a novel G-protein gamma-subunit from Arabidopsis thaliana andits interaction with G beta, BBA-GENE ST, 1520(2), 2001, pp. 147-153
Citations number
43
Categorie Soggetti
Molecular Biology & Genetics
Journal title
BIOCHIMICA ET BIOPHYSICA ACTA-GENE STRUCTURE AND EXPRESSION
There is increasing evidence that heterotrimeric G-proteins (G-proteins) ar
e involved in many plant processes including phytohormone response, pathoge
n defence and stomatal control. In animal systems, each of the three G-prot
ein subunits belong to large multigene families; however, few subunits have
been isolated from plants. Here we report the cloning of a second plant G-
protein gamma -subunit (AGG2) from Arabidopsis thaliana. The predicted AGG2
protein sequence shows 48% identity to the first identified Arabidopsis G
gamma -subunit, AGG1. Furthermore, AGG2 contains all of the conserved chara
cteristics of gamma -subunits including a small size (100 amino acids, 11.1
kDa), C-terminal CAAX box and a N-terminal alpha -helix region capable of
forming a coiled-coil interaction with the beta -subunit. A strong interact
ion between AGG2 and both the tobacco (TGB1) and Arabidopsis (AGB1) beta -s
ubunits was observed in vivo using the yeast two-hybrid system. The strong
association between AGG2 and AGB1 was confirmed in vitro. Southern and Nort
hern analyses showed that AGG2 is a single copy gene in Arabidopsis produci
ng two transcripts that are present in all tissues tested. The isolation of
a second gamma -subunit from A. thaliana indicates that plant G-proteins,
like their mammalian counterparts, may form different heterotrimer combinat
ions that presumably regulate multiple signal transduction pathways. (C) 20
01 Elsevier Science B.V. All rights reserved.