Yeast synaptobrevin, Snc1, engages distinct routes of postendocytic recycling mediated by a sorting nexin, Rcy1-COPI, and retromer

Mol Biol Cell. 2020 Apr 15;31(9):944-962. doi: 10.1091/mbc.E19-05-0290. Epub 2020 Feb 19.

Abstract

The budding yeast v-SNARE, Snc1, mediates fusion of exocytic vesicles to the plasma membrane (PM) and is subsequently recycled back to the Golgi. Postendocytic recycling of Snc1 requires a phospholipid flippase (Drs2-Cdc50), an F-box protein (Rcy1), a sorting nexin (Snx4-Atg20), and the COPI coat complex. A portion of the endocytic tracer FM4-64 is also recycled back to the PM after internalization. However, the relationship between Snx4, Drs2, Rcy1, and COPI in recycling Snc1 or FM4-64 is unclear. Here we show that rcy1∆ and drs2∆ single mutants, or a COPI mutant deficient in ubiquitin binding, display a defect in recycling FM4-64 while snx4∆ cells recycle FM4-64 normally. The addition of latrunculin A to acutely inhibit endocytosis shows that rcy1∆ and snx4∆ single mutants retain the ability to recycle Snc1, but a snx4∆rcy1∆ mutant substantially blocks export. Additional deletion of a retromer subunit completely eliminates recycling of Snc1 in the triple mutant (snx4∆rcy1∆vps35∆). A minor role for retromer in Snc1 recycling can also be observed in single and double mutants harboring vps35∆. These data support the existence of three distinct and parallel recycling pathways mediated by Drs2/Rcy1/COPI, Snx4-Atg20, and retromer that retrieve an exocytic v-SNARE from the endocytic pathway to the Golgi.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Calcium-Transporting ATPases / metabolism
  • Cell Membrane
  • Coat Protein Complex I / metabolism
  • F-Box Proteins / metabolism
  • R-SNARE Proteins / metabolism*
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae / physiology
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Sorting Nexins / metabolism*
  • Transport Vesicles / physiology*
  • Vesicular Transport Proteins / metabolism

Substances

  • Coat Protein Complex I
  • DRS2 protein, S cerevisiae
  • F-Box Proteins
  • R-SNARE Proteins
  • RCY1 protein, S cerevisiae
  • SNC1 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Sorting Nexins
  • Vesicular Transport Proteins
  • Calcium-Transporting ATPases