Exocytotic insertion of calcium channels constrains compensatory endocytosis to sites of exocytosis

Robert M. Smith, Boris Baibakov, Yoshihide Ikebuchi, Benjamin H. White, Nevin A Lambert, Leonard K. Kaczmarek, Steven S. Vogel

Research output: Contribution to journalArticlepeer-review

57 Scopus citations


Proteins inserted into the cell surface by exocytosis are thought to be retrieved by compensatory endocytosis, suggesting that retrieval requires granule proteins. In sea urchin eggs, calcium influx through P-type calcium channels is required for retrieval, and the large size of sea urchin secretory granules permits the direct observation of retrieval. Here we demonstrate that retrieval is limited to sites of prior exocytosis. We tested whether channel distribution can account for the localization of retrieval at exocytotic sites. We find that P-channels reside on secretory granules before fertilization, and are translocated to the egg surface by exocytosis. Our study provides strong evidence that the transitory insertion of P-type calcium channels in the surface membrane plays an obligatory role in the mechanism coupling exocytosis and compensatory endocytosis.

Original languageEnglish (US)
Pages (from-to)755-767
Number of pages13
JournalJournal of Cell Biology
Issue number4
StatePublished - Feb 21 2000


  • Agatoxin
  • Conotoxin
  • Microscopy
  • P-type calcium channels
  • Sea urchins

ASJC Scopus subject areas

  • Cell Biology


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