Poster Session II
Project Type
Poster
Project Funding and Affiliations
DBS, CBSD, INBRE
Faculty Mentor’s Full Name
Levi McClelland
Faculty Mentor’s Department
Division of Biological Science
Abstract / Artist's Statement
Author: Fiona Morrow
Conference: 2026 UMCUR
Title: Investigation of Guanine Exchange by Ric8A for Gαi
Abstract: Ric8 is a chaperone protein for the Gα subunit of the G protein coupled receptor, the most common and diverse membrane receptor group in eukaryotic cells. Signal transduction across the cell membrane uses the G protein complex, with an integral G protein that spans the entire membrane and 3 bound subunits on the interior side of the membrane. When a ligand binds on the GPCR, the 3 interior subunits dissociate and carry the signal to the next step of the cascade; this dissociation is predicated by a nucleotide exchange on the Gα subunit, which has a GDP bound when inactive (associated) and GTP bound when active (dissociated). The Gα subunit has an intrinsic ability to exchange GDP for GTP, but the Ric8 chaperone protein greatly increases the rate of nucleotide exchange. The purpose of this project was to identify potential Gα binding sites on the Ric8 protein and assess the nucleotide exchange behavior of different Ric8 mutants. The mutants created for these assays targeted specific potentially catalytic amino acids based off the structure of Ric8 bound to Gα, and catalytic activity was measured for each using fluorescence spectroscopy. By comparing the reaction rate for each Ric8 mutant to the reaction rate of wild type Ric 8 and the intrinsic reaction rate of Gα, the effect of mutating each amino acid residue can be compared to normal function for both proteins.
Category
Life Sciences
Investigation of Guanine Exchange by Ric8A for Gαi
UC South Ballroom
Author: Fiona Morrow
Conference: 2026 UMCUR
Title: Investigation of Guanine Exchange by Ric8A for Gαi
Abstract: Ric8 is a chaperone protein for the Gα subunit of the G protein coupled receptor, the most common and diverse membrane receptor group in eukaryotic cells. Signal transduction across the cell membrane uses the G protein complex, with an integral G protein that spans the entire membrane and 3 bound subunits on the interior side of the membrane. When a ligand binds on the GPCR, the 3 interior subunits dissociate and carry the signal to the next step of the cascade; this dissociation is predicated by a nucleotide exchange on the Gα subunit, which has a GDP bound when inactive (associated) and GTP bound when active (dissociated). The Gα subunit has an intrinsic ability to exchange GDP for GTP, but the Ric8 chaperone protein greatly increases the rate of nucleotide exchange. The purpose of this project was to identify potential Gα binding sites on the Ric8 protein and assess the nucleotide exchange behavior of different Ric8 mutants. The mutants created for these assays targeted specific potentially catalytic amino acids based off the structure of Ric8 bound to Gα, and catalytic activity was measured for each using fluorescence spectroscopy. By comparing the reaction rate for each Ric8 mutant to the reaction rate of wild type Ric 8 and the intrinsic reaction rate of Gα, the effect of mutating each amino acid residue can be compared to normal function for both proteins.