Cis- and trans-acting functions required for endocytosis of the yeast pheromone receptors

• Published in: The Journal of cell biology 1993-07, Vol.122 (1), p.53-65
• Main Authors: Davis, N.G, Horecka, J.L, Sprague, G.F. Jr
• Format: Article
• Language: English
• Subjects: ABSORCION; ABSORPTION; Antibodies; Antiserum; Biological and medical sciences; Cell physiology; Cells; Cellular biology; CHIMIORECEPTEUR; Crosses, Genetic; Endocytosis; FEROMONAS; Fundamental and applied biological sciences. Psychology; GENE; GENES; Genes, Fungal; Genes, myc; Genotype; GTP-Binding Proteins - metabolism; Internalization; Ligands; Molecular and cellular biology; MUTACION INDUCIDA; Mutagenesis; MUTANT; MUTANTES; MUTATION PROVOQUEE; PHEROMONE; Pheromones; Proteins; QUIMIORECEPTORS; Receptors; Receptors, Cell Surface - genetics; Receptors, Cell Surface - metabolism; Receptors, G-Protein-Coupled; Receptors, Mating Factor; Receptors, Peptide; Receptors, Pheromone; SACCHAROMYCES CEREVISIAE; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins; SEXE; SEXO; Spheroplasts - metabolism; Transcription Factors - metabolism; VACUOLA; VACUOLE; Vacuoles; Vacuoles - enzymology; Vacuoles - metabolism; Yeast; Yeasts
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.122.1.53

The Saccharomyces cerevisiae a-factor receptor (STE3) is subject to two modes of endocytosis: a constitutive process that occurs in the absence of ligand and a regulated process that is triggered by binding of ligand. Both processes result in delivery of the receptor to the vacuole for degradation. Receptor mutants deleted for part of the COOH-terminal cytoplasmic domain are disabled for constitutive, but not ligand-dependent internalization. Trans-acting mutants that impair constitutive endocytosis have been isolated. One of these, ren1-1, is blocked at a late step in the endocytic pathway, as receptor accumulates in a prevacuolar endosome-like compartment. REN1 is identical to VPS2, a gene required for delivery of newly synthesized vacuolar enzymes to the vacuole. Based on this identity, we suggest a model in which the transport pathways to the vacuole--the endocytic pathway and the vacuolar biogenesis pathway--merge at an intermediate endocytic compartment. As receptor also accumulates at the surface of ren1 cells, receptor may recycle from the putative endosome to the surface, or REN1 may also be required to carry out an early step in endocytosis