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Stanley Fields

Publications and source records attributed to Stanley Fields.

41 records · Page 3Linked to original sources

Analysis of membrane protein interactions using yeast-based technologies.

Proteins associated with membranes total approximately a third of all proteins in a typical eukaryotic cell. However, the analysis of interactions between membrane proteins is difficult because of the hydrophobic nature of these proteins, and conventional biochemical and genetic assays are often of limited use. We summarize here recent yeast-based interaction technologies that can be applied to membrane proteins.

Membrane Proteins↗

A genome-wide screen for site-specific DNA-binding proteins.

We used a biochemical genomics method of assaying Saccharomyces cerevisiae proteins, derived from a nearly complete set of glutathione S-transferase fusions, to develop an approach that is able to identify proteins that bind to a DNA element. Using the upstream activation sequence (UAS) of the promoter for the invertase gene, SUC2, we identified both specific and nonspecific binding activities, which could be classified based on whether they bound with equivalent affinity to a nonspecific DNA competitor. Three transcription factors, Mig1, Yer028c, and Rgt1, were found to be binding activities specific to the SUC2 UAS. Mig1 and Yer028c had been reported previously to bind to elements within the SUC2 UAS, validating the ability of the method to identify sequence-specific factors. The third activity, Rgt1, had not been reported previously to bind to SUC2. Additional gel shift assays narrowed the Rgt1 binding site to the SUC2-B element within the SUC2 UAS, which is similar to previously identified Rgt1 binding sites present in other genes. In vivo levels of invertase activity in an rgt1Delta strain were reduced relative to an isogenic RGT+ strain when these strains were grown under inducing (low glucose) conditions, suggesting that Rgt1 may have a role in the activated transcription of SUC2. This report demonstrates the feasibility of identifying DNA binding activities by rapidly assaying a large fraction of the predicted open reading frames of an organism for binding to a regulatory DNA motif.

Binding Sites↗

A combined experimental and computational strategy to define protein interaction networks for peptide recognition modules.

Peptide recognition modules mediate many protein-protein interactions critical for the assembly of macromolecular complexes. Complete genome sequences have revealed thousands of these domains, requiring improved methods for identifying their physiologically relevant binding partners. We have developed a strategy combining computational prediction of interactions from phage-display ligand consensus sequences with large-scale two-hybrid physical interaction tests. Application to yeast SH3 domains generated a phage-display network containing 394 interactions among 206 proteins and a two-hybrid network containing 233 interactions among 145 proteins. Graph theoretic analysis identified 59 highly likely interactions common to both networks. Las17 (Bee1), a member of the Wiskott-Aldrich Syndrome protein (WASP) family of actin-assembly proteins, showed multiple SH3 interactions, many of which were confirmed in vivo by coimmunoprecipitation.

Algorithms↗