Distinct complexes of yeast Snx4 family SNX-BARs mediate retrograde trafficking of Snc1 and Atg27.

Mengxiao Ma, Christopher G Burd, Richard J Chi

Traffic (Copenhagen, Denmark) 2017 Feb

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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. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Citation

Mengxiao Ma, Christopher G Burd, Richard J Chi. Distinct complexes of yeast Snx4 family SNX-BARs mediate retrograde trafficking of Snc1 and Atg27. Traffic (Copenhagen, Denmark). 2017 Feb;18(2):134-144