t-SNARE phosphorylation regulates endocytosis in yeast
| Autor: | Jeffrey E. Gerst, Michael Marash, Adina Weinberger, Sangiliyandi Gurunathan |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Saccharomyces cerevisiae Proteins
Receptors Peptide Macromolecular Substances Endocytic cycle Phosphatase Pyridinium Compounds Vacuole Biology Endocytosis Ligands Exocytosis Article Dephosphorylation Fungal Proteins R-SNARE Proteins Sphingosine Yeasts Phosphoprotein Phosphatases Secretion Phosphorylation Transport Vesicles Molecular Biology Qa-SNARE Proteins Phosphotransferases Membrane Proteins Membrane Transport Proteins Cell Biology Cell biology Quaternary Ammonium Compounds Receptors Mating Factor Transcription Factors |
| Zdroj: | Molecular biology of the cell. 13(5) |
| ISSN: | 1059-1524 |
| Popis: | Earlier we demonstrated that activation of a ceramide-activated protein phosphatase (CAPP) conferred normal growth and secretion to yeast lacking their complement of exocytic v-SNAREs (Snc1,2) or bearing a temperature-sensitive mutation in an exocytic t-SNARE (Sso2). CAPP activation led to Sso dephosphorylation and enhanced the assembly of t-SNAREs into functional complexes. Thus, exocytosis in yeast is modulated by t-SNARE phosphorylation. Here, we show that endocytic defects in cells lacking the v- and t-SNAREs involved in endocytosis are also rescued by CAPP activation. Yeast lacking the Tlg1 or Tlg2 t-SNAREs, the Snc v-SNAREs, or both, undergo endocytosis after phosphatase activation. CAPP activation correlated with restored uptake of FM4-64 to the vacuole, the uptake and degradation of the Ste2 receptor after mating factor treatment, and the dephosphorylation and assembly of Tlg1,2 into SNARE complexes. Activation of the phosphatase by treatment with C2-ceramide,VBM/ELO gene inactivation, or by the overexpression of SIT4 was sufficient to confer rescue. Finally, we found that mutation of single PKA sites in Tlg1 (Ser31 to Ala31) or Tlg2 (Ser90 to Ala90) was sufficient to restore endocytosis, but not exocytosis, to snc cells. These results suggest that endocytosis is also modulated by t-SNARE phosphorylation in vivo. |
| Databáze: | OpenAIRE |
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