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Selective Recapture of Secretory Granule Components After Full Collapse Exocytosis in Neuroendocrine Chromaffin Cells
Author(s) -
Ceridono Mara,
Ory Stéphane,
Momboisse Fanny,
ChasserotGolaz Sylvette,
Houy Sébastien,
Calco Valérie,
Haeberlé AnneMarie,
Demais Valérie,
Bailly Yannick,
Bader MarieFrance,
Gasman Stéphane
Publication year - 2011
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2010.01125.x
Subject(s) - exocytosis , granule (geology) , microbiology and biotechnology , endocytosis , biology , secretion , lipid bilayer fusion , internalization , membrane , biochemistry , cell , paleontology
In secretory cells, calcium‐regulated exocytosis is rapidly followed by compensatory endocytosis. Neuroendocrine cells secrete hormones and neuropeptides through various modes of exo‐endocytosis, including kiss‐and‐run, cavicapture and full‐collapse fusion. During kiss‐and‐run and cavicapture modes, the granule membrane is maintained in an omega shape, whereas it completely merges with the plasma membrane during full‐collapse mode. As the composition of the granule membrane is very different from that of the plasma membrane, a precise sorting process of granular proteins must occur. However, the fate of secretory granule membrane after full fusion exocytosis remains uncertain.Here, we investigated the mechanisms governing endocytosis of collapsed granule membranes by following internalization of antibodies labeling the granule membrane protein, dopamine‐β‐hydroxylase (DBH) in cultured chromaffin cells. Using immunofluorescence and electron microscopy, we observed that after full collapse, DBH remains clustered on the plasma membrane with other specific granule markers and is subsequently internalized through vesicular structures composed mainly of granule components. Moreover, the incorporation of this recaptured granule membrane into an early endosomal compartment is dependent on clathrin and actin. Altogether, these results suggest that after full collapse exocytosis, a selective sorting of granule membrane components is facilitated by the physical preservation of the granule membrane entity on the plasma membrane.