A Post-Docking Role of Synaptotagmin 1-C2B Domain Bottom Residues R398/399 in Mouse Chromaffin Cells.
Girish H KedarAnders S MunchJan R T van WeeringJörg MalsamAndrea ScheutzowHeidi de WitSébastien HouyBassam TawfikThomas H SöllnerJakob Balslev SørensenMatthijs VerhagePublished in: The Journal of neuroscience : the official journal of the Society for Neuroscience (2016)
This study provides new insights in how the two opposite sides of the C2B domain of Synaptotagmin-1 participate in secretory vesicle fusion, and in more upstream steps, especially vesicle docking. We show that the "bottom" surface of the C2B domain is required for triggering fusion, but not for docking. Synaptotagmin-1 promotes docking by multiple, PI(4,5)P2-dependent and PI(4,5)P2-independent mechanisms. Mutations in the C2B bottom surface (R398/399) selectively disrupt the latter. These mutations help to discriminate protein regions involved in different aspects of Synaptotagmin-1 function in docking and fusion.