Phosphorylation of residues inside the SNARE complex suppresses secretory vesicle fusion |
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| Authors: | Seth Malmersjö Serena Di Palma Jiajie Diao Ying Lai Richard A Pfuetzner Austin L Wang Moira A McMahon Arnold Hayer Matthew Porteus Bernd Bodenmiller Axel T Brunger Tobias Meyer |
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| Institution: | 1. Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA;2. Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland;3. Functional Genomics Center Zurich, ETH Zurich/University of Zurich, Zurich, Switzerland;4. Departments of Molecular and Cellular Physiology, Neurology and Neurological Sciences, Photon Science, and Structural Biology, Stanford University, Stanford, CA, USA;5. Howard Hughes Medical Institute, Stanford, CA, USA;6. Department of Pediatrics, Stanford University, Stanford, CA, USA |
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| Abstract: | Membrane fusion is essential for eukaryotic life, requiring SNARE proteins to zipper up in an α‐helical bundle to pull two membranes together. Here, we show that vesicle fusion can be suppressed by phosphorylation of core conserved residues inside the SNARE domain. We took a proteomics approach using a PKCB knockout mast cell model and found that the key mast cell secretory protein VAMP8 becomes phosphorylated by PKC at multiple residues in the SNARE domain. Our data suggest that VAMP8 phosphorylation reduces vesicle fusion in vitro and suppresses secretion in living cells, allowing vesicles to dock but preventing fusion with the plasma membrane. Markedly, we show that the phosphorylation motif is absent in all eukaryotic neuronal VAMPs, but present in all other VAMPs. Thus, phosphorylation of SNARE domains is a general mechanism to restrict how much cells secrete, opening the door for new therapeutic strategies for suppression of secretion. |
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| Keywords: | mast cell degranulation protein kinase C secretion SNARE complex VAMP8 |
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