title: Integrating energy calculations with functional assays to decipher the specificity of G protein-RGS protein interactions.
abstract: The diverse Regulator of G protein Signaling (RGS) family sets the timing of G protein signaling. To understand how the structure of RGS proteins determines their common ability to inactivate G proteins and their selective G protein recognition, we combined structure-based energy calculations with biochemical measurements of RGS activity. We found a previously unidentified group of variable 'Modulatory' residues that reside at the periphery of the RGS domain-G protein interface and fine-tune G protein recognition. Mutations of Modulatory residues in high-activity RGS proteins impaired RGS function, whereas redesign of low-activity RGS proteins in critical Modulatory positions yielded complete gain of function. Therefore, RGS proteins combine a conserved core interface with peripheral Modulatory residues to selectively optimize G protein recognition and inactivation. Finally, we show that our approach can be extended to analyze interaction specificity across other large protein families.
authors.affiliation: Duke Eye Center, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Mickey
authors.initials: M
authors.lastname: Kosloff
authors.forename: Amanda M
authors.initials: AM
authors.lastname: Travis
authors.forename: Dustin E
authors.initials: DE
authors.lastname: Bosch
authors.forename: David P
authors.initials: DP
authors.lastname: Siderovski
authors.forename: Vadim Y
authors.initials: VY
authors.lastname: Arshavsky
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D003087:Colicins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D020710:RGS Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D003087:Colicins; D020710:RGS Proteins; D019204:GTP-Binding Proteins