G Proteins, Plant Growth, and Parasite Invasion

Abstract

The function of regulators of G protein signaling (RGSs) is just as the name indicates--in mammals and yeast, these proteins attenuate signals initiated by G protein-coupled receptors (GPCRs) at the cell surface. Chen et al. have now identified an RGS protein in Arabidopsis that functions together with a heterotrimeric G protein to control root and shoot growth. The plant RGS behaves biochemically like a bona fide family member, yet its sequence predicts a protein that contains a seven-transmembrane spanning region similar to GPCRs, quite unlike other known RGS proteins. The process of invasion of red blood cells by the malaria parasite Plasmodium falciparum is fundamental to disease progression. Harrison et al. reveal the requirement for GPCR activation in the host erythrocyte cell membrane to allow successful invasion. It is likely that the activated receptors promote the rearrangement of the rigid erythrocyte subcortical cytoskeleton to allow for the deformation of the membrane required during parasite invasion. J.-G. Chen, F. S. Willard, J. Huang, J. Liang, S. A. Chasse, A. M. Jones, D. P. Siderovski, A seven-transmembrane RGS protein that modulates plant cell proliferation. Science 301 , 1728-1731 (2003). [Abstract] [Full Text] T. Harrison, B. U. Samuel, T. Akompong, H. Hamm, N. Mohandas, J. W. Lomasney, K. Haldar, Erythrocyte G protein-coupled receptor signaling in malarial infection. Science 301 , 1734-1736 (2003). [Abstract] [Full Text]