Ceramide chain length–dependent protein sorting into selective endoplasmic reticulum exit sites

Description

Protein sorting in the secretory pathway is crucial to maintain cellular compartmentalization and homeostasis. In addition to coat-mediated sorting, the role of lipids in driving protein sorting during secretory transport is a longstanding fundamental question that still remains unanswered. Here, we conduct 3D simultaneous multicolor high-resolution live imaging to demonstrate in vivo that newly synthesized glycosylphosphatidylinositol-anchored proteins having a very long chain ceramide lipid moiety are clustered and sorted into specialized endoplasmic reticulum exit sites that are distinct from those used by transmembrane proteins. Furthermore, we show that the chain length of ceramide in the endoplasmic reticulum membrane is critical for this sorting selectivity. Our study provides the first direct in vivo evidence for lipid chain length–based protein cargo sorting into selective export sites of the secretory pathway.

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Spanish Ministry of Economy and Competitiveness (MINECO; grant number BFU2017-89700-P)

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University of Seville (VIPPIT-2020-I.5)

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Japan Society for the Promotion of Science (JP25221103, JP17H06420, and JP18H05275)

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Swiss National Science Foundation (grant no. 163966)

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Swiss National Supercomputing Centre (CSCS) under project IDs s726 and s842

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