title: Maintaining protein homeostasis: early and late endosomal dual recycling for the maintenance of intracellular pools of the plasma membrane protein Chs3.
abstract: The major chitin synthase activity in yeast cells, Chs3, has become a paradigm in the study of the intracellular traffic of transmembrane proteins due to its tightly regulated trafficking. This includes an efficient mechanism for the maintenance of an extensive reservoir of Chs3 at the trans-Golgi network/EE, which allows for the timely delivery of the protein to the plasma membrane. Here we show that this intracellular reservoir of Chs3 is maintained not only by its efficient AP-1-mediated recycling, but also by recycling through the retromer complex, which interacts with Chs3 at a defined region in its N-terminal cytosolic domain. Moreover, the N-terminal ubiquitination of Chs3 at the plasma membrane by Rsp5/Art4 distinctly labels the protein and regulates its retromer-mediated recycling by enabling Chs3 to be recognized by the ESCRT machinery and degraded in the vacuole. Therefore the combined action of two independent but redundant endocytic recycling mechanisms, together with distinct labels for vacuolar degradation, determines the final fate of the intracellular traffic of the Chs3 protein, allowing yeast cells to regulate morphogenesis, depending on environmental constraints.
authors: IBFG and Departamento de Microbiología y Genética, CSIC/Universidad de Salamanca, 37007 Salamanca, Spain.
authors: Irene
authors: I
authors: Arcones
authors: IBFG and Departamento de Microbiología y Genética, CSIC/Universidad de Salamanca, 37007 Salamanca, Spain.
authors: Carlos
authors: C
authors: Sacristán
authors: IBFG and Departamento de Microbiología y Genética, CSIC/Universidad de Salamanca, 37007 Salamanca, Spain crm@usal.es.
authors: Cesar
authors: C
authors: Roncero
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D002687:Chitin Synthase / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis / Q000502:physiology; D056827:Endosomal Sorting Complexes Required for Transport / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D021381:Protein Transport; D059748:Proteolysis; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination; D014617:Vacuoles / Q000378:metabolism; D021601:trans-Golgi Network / Q000378:metabolism
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins; C069390:CHS3 protein, S cerevisiae; D002687:Chitin Synthase