Post-fusion structural changes and their roles in exocytosis and endocytosis of dense-core vesicles

Hsueh Cheng Chiang, Wonchul Shin, Wei Dong Zhao, Edaeni Hamid, Jiansong Sheng, Maryna Baydyuk, Peter J. Wen, Albert Jin, Fanny Momboisse, Ling Gang Wu

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)

Abstract

Vesicle fusion with the plasma membrane generates an Ω-shaped membrane profile. Its pore is thought to dilate until flattening (full-collapse), followed by classical endocytosis to retrieve vesicles. Alternatively, the pore may close (kiss-and-run), but the triggering mechanisms and its endocytic roles remain poorly understood. Here, using confocal and stimulated emission depletion microscopy imaging of dense-core vesicles, we find that fusion-generated Ω-profiles may enlarge or shrink while maintaining vesicular membrane proteins. Closure of fusion-generated Ω-profiles, which produces various sizes of vesicles, is the dominant mechanism mediating rapid and slow endocytosis within ∼1-30 s. Strong calcium influx triggers dynamin-mediated closure. Weak calcium influx does not promote closure, but facilitates the merging of Ω-profiles with the plasma membrane via shrinking rather than full-collapse. These results establish a model, termed Ω-exo-endocytosis, in which the fusion-generated Ω-profile may shrink to merge with the plasma membrane, change in size or change in size then close in response to calcium, which is the main mechanism to retrieve dense-core vesicles.

Original languageEnglish
Article number3356
JournalNature communications
Volume5
DOIs
Publication statusPublished - 2014 Feb 24

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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