ALIX and ceramide differentially control polarized small extracellular vesicle release from epithelial cells

Takahide Matsui, Futaba Osaki, Shu Hiragi, Yuriko Sakamaki, Mitsunori Fukuda

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Exosomes, important players in cell–cell communication, are small extracellular vesicles of endocytic origin. Although single cells are known to release various kinds of exosomes (referred to as exosomal heterogeneity), very little is known about the mechanisms by which they are produced and released. Here, we established methods of studying exosomal heterogeneity by using polarized epithelial cells and showed that distinct types of small extracellular vesicles (more specifically CD9- and CD63-positive, Annexin I-negative small extracellular vesicles, which we refer to as exosomes herein) are differentially secreted from the apical and basolateral sides of polarized epithelial cells. We also identify GPRC5C (G protein-coupled receptor class C group 5 member C) as an apical exosome-specific protein. We further demonstrate that basolateral exosome release depends on ceramide, whereas ALIX, an ESCRT (endosomal sorting complexes required for transport)-related protein, not the ESCRT machinery itself, is required for apical exosome release. Thus, two independent machineries, the ALIX–Syntenin1–Syndecan1 machinery (apical side) and the sphingomyelinase-dependent ceramide production machinery (basolateral side), are likely to be responsible for the polarized exosome release from epithelial cells.

Original languageEnglish
Article numbere51475
JournalEMBO Reports
Issue number5
Publication statusPublished - 2021 May 5


  • ceramide
  • exosome
  • multivesicular body
  • small extracellular vesicle

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Genetics


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