title: Distinct complexes of yeast Snx4 family SNX-BARs mediate retrograde trafficking of Snc1 and Atg27.
abstract: The yeast SNX4 sub-family of sorting nexin containing a Bin-Amphiphysin-Rvs domain (SNX-BAR) proteins, Snx4/Atg24, Snx41 and Atg20/Snx42, are required for endocytic recycling and selective autophagy. Here, we show that Snx4 forms 2 functionally distinct heterodimers: Snx4-Atg20 and Snx4-Snx41. Each heterodimer coats an endosome-derived tubule that mediates retrograde sorting of distinct cargo; the v-SNARE, Snc1, is a cargo of the Snx4-Atg20 pathway, and Snx4-Snx41 mediates retrograde sorting of Atg27, an integral membrane protein implicated in selective autophagy. Live cell imaging of individual endosomes shows that Snx4 and the Vps5-Vps17 retromer SNX-BAR heterodimer operate concurrently on a maturing endosome. Consistent with this, the yeast dynamin family protein, Vps1, which was previously shown to promote fission of retromer-coated tubules, promotes fission of Snx4-Atg20 coated tubules. The results indicate that the yeast SNX-BAR proteins coat 3 distinct types of endosome-derived carriers that mediate endosome-to-Golgi retrograde trafficking.
authors.affiliation: Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut.
authors.forename: Mengxiao
authors.initials: M
authors.lastname: Ma
authors.affiliation: Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut.
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Burd
authors.affiliation: Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Chi
mesh_terms: D002352:Carrier Proteins / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology*; D050683:R-SNARE Proteins / Q000378:metabolism*; D058305:Sorting Nexins / Q000378:metabolism*; D033921:Vesicular Transport Proteins / Q000378:metabolism; D015003:Yeasts / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D005656:Fungal Proteins; D050683:R-SNARE Proteins; D058305:Sorting Nexins; D033921:Vesicular Transport Proteins
keywords: 
  SNX-BAR
  ; Atg27; Vps1; autophagy; endosome; retromer