The RGS proteins add to the diversity of soybean heterotrimeric G-protein signaling

Abstract

Regulator of G-protein signaling (RGS) proteins are a family of highly diverse, multifunctional proteins that function primarily as GTPase accelerating proteins (GAPs). RGS proteins increase the rate of GTP hydrolysis by Gα proteins and essentially regulate the duration of active signaling. Recently, we have identified two chimeric RGS proteins from soybean and reported their distinct GAP activities on individual Gα proteins. A single amino acid substitution (Alanine 357 to Valine) of RGS2 is responsible for differential GAP activity. Surprisingly, most monocot plant genomes do not encode for a RGS protein homolog. Here we discuss the soybean RGS proteins in the context of their evolution in plants, their relatedness to non-plant RGS protein homologs and the effect they might have on the heterotrimeric G-protein signaling mechanisms. We also provide experimental evidence to show that the interaction interface between plant RGS and Gα proteins is different from what is predicted based on mammalian models.

Keywords: :

• RGS proteins
• heterotrimeric G-proteins
• soybean
• protein-protein interaction
• G-protein evolution

Disclosure of Conflict of Interest

No potential conflicts of interest were disclosed.

Acknowledgments

This work is supported by the Agriculture and Food Research Initiative Competitive Grants Program grant no. 2010–65116–20454 from the USDA National Institute of Food and Agriculture. C.S.W. was supported by a US. Department of Agriculture/Agriculture and Food Research Initiative pre-doctoral research fellowship (MOW-2010–05240).