Following is a description of a recently published research paper recommended by a scientist involved in integrated biology. The recommender, Steven Lund, is assistant professor of viticulture and plant genomics at the Universityof British Columbia.
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The Arabidopsis Putative G Protein-Coupled Receptor GCR1 Interacts with the G Protein a Subunit GPA1 and Regulates Abscisic Acid Signaling
Pandey S, Assmann, S. The Plant Cell. 2004 Jun; 16: 1616-1632.
Lead author Sarah Assmann and co-author Sona Pandey, both at PennStateUniversity, describe their attempts to investigate the interactions of G protein-coupled receptors encoded by the Arabidopsis thaliana genome. The Arabidopsis genome encodes single prototypical Gα (GPA1) and Gß (AGB1) subunits, and two probable Gγ subunits (AGG1 and AGG2). One Arabidopsis gene, GCR1, encodes a protein with significant sequence similarity to nonplant GPCRs and a predicted 7-transmembrane domain structure characteristic of GPCRs. However, whether GCR1 actually interacts with GPA1 was unknown. They demonstrate by in vitro pull-down assays, by yeast split-ubiquitin assays, and by coimmunoprecipitation from plant tissue that GCR1 and GPA1 are indeed physically coupled.
Lundsays this paper is important because it presents evidence that the heterotrimeric protein complex in G proteins - of which only one exists in plants - potentially functions as a receptor for abscisic acid, a major plant hormone. 'This is a major breakthrough because there's not been any really clear, definitive evidence prior as to how the ABAhormone might be perceived,' he says. The paper also suggests, Lundsays, that ABAmight be one of the major hormones promoting the initiation of ripening in non-climacteric plants like grapes, strawberries, and oranges, findings that could lead to new targets for genetic modifications for agricultural applications.
Assistant Professor of Viticulture/Plant Genomics
Universityof British Columbia