Synaptotagmin II Negatively Regulates Ca2+-triggered Exocytosis of Lysosomes in Mast Cells
| Autor: | Roberto Adachi, Dana Baram, Burton F. Dickey, Ronit Sagi-Eisenberg, Yoseph A. Mekori, Ora Medalia, Michael J. Tuvim |
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| Rok vydání: | 1999 |
| Předmět: |
Serotonin
Immunology Cathepsin D Nerve Tissue Proteins mast cells Neurotransmission Biology Cytoplasmic Granules Transfection Exocytosis calcium binding proteins immunoglobulin E Lysosomal exocytosis Synaptotagmins Mice lysosomes Synaptotagmin II medicine Animals Immunology and Allergy Secretion RNA Messenger Rats Wistar Calcimycin Mice Inbred BALB C Receptors IgE Articles Mast cell beta-N-Acetylhexosaminidases Rats Cell biology medicine.anatomical_structure Gene Expression Regulation Tetradecanoylphorbol Acetate Calcium |
| Zdroj: | The Journal of Experimental Medicine |
| ISSN: | 1540-9538 0022-1007 |
| DOI: | 10.1084/jem.189.10.1649 |
| Popis: | Synaptotagmins (Syts) I and II are believed to act as Ca2+ sensors in the control of neurotransmission. Here we demonstrate that mast cells express Syt II in their lysosomal fraction. We further show that activation of mast cells by either aggregation of FcεRI or by Ca2+ ionophores results in exocytosis of lysosomes, in addition to the well documented exocytosis of their secretory granules. Syt II directly regulates lysosomal exocytosis, whereby overexpression of Syt II inhibited Ca2+-triggered release of the lysosomal processed form of cathepsin D, whereas suppression of Syt II expression markedly potentiated this release. These findings provide evidence for a novel function of Syt II in negatively regulating Ca2+-triggered exocytosis of lysosomes, and suggest that Syt II–regulated secretion from lysosomes may play an important role in mast cell biology. |
| Databáze: | OpenAIRE |
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