Role of extracellular charged amino acids in the yeast alpha-factor receptor.
The yeast pheromone receptor, Ste2p, is a G protein coupled receptor that initiates cellular responses to alpha-mating pheromone, a 13 residue peptide that carries a net positive charge at physiological pH. We have examined the role of extracellular charged groups on the receptor in response to the pheromone. Substitutions of Asn or Ala for one extracellular residue, Asp275, affected both pheromone binding and signaling, suggesting that this position interacts directly with ligand. The other seven extracellular acidic residues could be individually replaced by polar residues with no detectable effects on receptor function. However, substitution of Ala for each of these seven residues resulted in impairment of signaling without affecting pheromone binding, implying that the polar nature of these residues promotes receptor activation. In contrast, substitution of Ala for each of the six positively charged residues at the extracellular surface of Ste2p did not affect signaling.
Bajaj
Anshika
A
Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester, School of Medicine and Dentistry, Rochester, NY 14642, USA.
Connelly
Sara M
SM
Gehret
Austin U
AU
Naider
Fred
F
Dumont
Mark E
ME
D019943:Amino Acid Substitution; D024361:Amino Acids, Basic / Q000235:genetics / Q000378:metabolism*; D001224:Aspartic Acid / Q000235:genetics / Q000378:metabolism*; D000072235:Mating Factor; D020125:Mutation, Missense; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D051964:Receptors, Mating Factor / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
D024361:Amino Acids, Basic; D010455:Peptides; D043562:Receptors, G-Protein-Coupled; D051964:Receptors, Mating Factor; C498031:STE2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D001224:Aspartic Acid; D000072235:Mating Factor