Abstract
Heterotrimeric G-proteins comprised of Gα, Gβ and Gγ proteins are important signal transducers in all eukaryotes. The Gγ protein of the G-protein heterotrimer is crucial for its proper targeting at the plasma membrane and correct functioning. Gγ proteins are significantly smaller and more diverse than the Gα and Gβ proteins. In model plants Arabidopsis and rice that have a single Gα and Gβ protein, the presence of two canonical Gγ proteins provide some diversity to the possible heterotrimeric combinations. Our recent analysis of the latest version of the soybean genome has identified ten Gγ proteins which belong to three distinct families based on their C-termini. We amplified the full length cDNAs, analyzed their detailed expression profile by quantitative PCR, assessed their localization and performed yeast-based interaction analysis to evaluate interaction specificity with different Gβ proteins. Our results show that ten Gγ genes are retained in the soybean genome and have interesting expression profiles across different developmental stages. Six of the newly identified proteins belong to two plant-specific Gγ protein families. Yeast-based interaction analyses predict some degree of interaction specificity between different Gβ and Gγ proteins. This research thus identifies a highly diverse G-protein network from a plant species. Homologs of these novel proteins have been previously identified as QTLs for grain size and yield in rice.
Highlights
Heterotrimeric G-proteins comprised of three dissimilar subunits a, b and c are important signaling intermediates in all eukaryotes [1,2,3]
Identification of additional canonical and novel Gc proteins from the soybean genome Our previous analysis of the soybean genome had identified only two Gc proteins [10]
We performed a careful search with the newer version of the soybean genome and identified eight additional Gc proteins
Summary
Heterotrimeric G-proteins comprised of three dissimilar subunits a, b and c are important signaling intermediates in all eukaryotes [1,2,3]. The Ga subunit, due to its ability to switch between the GDP-bound inactive form and GTP-bound active form, defines the status of signal transduction. Ligand binding to the GPCR causes a change in its conformation allowing an exchange of GTP for GDP on the Ga subunit [4]. The GTPbound Ga dissociates from the Gbc subunits and the released GaNGTP and Gbc dimer interact with a variety of effector proteins to transduce the signal. The intrinsic GTPase activity of Ga causes GTP hydrolysis, converting it back to its GDP-bound state. The GaNGDP reassociates with the Gbc dimer and the proteins return back to trimeric conformation [4,5]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
