The carboxy-terminal segment of the yeast alpha-factor receptor is a regulatory domain.
The alpha-factor receptor is rapidly hyperphosphorylated on Thr and Ser residues in its hydrophilic C-terminal domain after cells are exposed to pheromone. Mutant receptors in which this domain is altered or removed are biologically active and bind alpha-factor with nearly normal affinity. However, cells expressing the mutant receptors are hypersensitive to pheromone action and appear to be defective in recovery from alpha-factor-induced growth arrest. Mutant receptors with partial C-terminal truncations undergo ligand-induced endocytosis, suggesting that down-regulation of receptor number is not the sole process for adaptation at the receptor level. A mutant receptor lacking the entire C-terminal domain (134 residues) does not display ligand-induced endocytosis. Genetic experiments indicate that the contribution of SST2 function to adaptation does not require the C-terminal domain of the receptor.
Reneke
J E
JE
Department of Biochemistry University of California, Berkeley 94720.
Blumer
K J
KJ
Courchesne
W E
WE
Thorner
J
J
D000595:Amino Acid Sequence; D000072235:Mating Factor; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D010455:Peptides / Q000378:metabolism*; D010675:Pheromones / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000032:analysis*; D051964:Receptors, Mating Factor; D018000:Receptors, Peptide; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D014157:Transcription Factors
D010446:Peptide Fragments; D010455:Peptides; D010675:Pheromones; D011956:Receptors, Cell Surface; D051964:Receptors, Mating Factor; D018000:Receptors, Peptide; D014157:Transcription Factors; D000072235:Mating Factor