TY - JOUR T1 - The Association of Dynamin with Synaptophysin Regulates Quantal Size and Duration of Exocytotic Events in Chromaffin Cells JF - The Journal of Neuroscience JO - J. Neurosci. SP - 10683 LP - 10691 DO - 10.1523/JNEUROSCI.5210-09.2010 VL - 30 IS - 32 AU - Arlek M. González-Jamett AU - Ximena Báez-Matus AU - Montserrat A. Hevia AU - María José Guerra AU - María José Olivares AU - Agustín D. Martínez AU - Alan Neely AU - Ana M. Cárdenas Y1 - 2010/08/11 UR - http://www.jneurosci.org/content/30/32/10683.abstract N2 - Although synaptophysin is one of the most abundant integral proteins of synaptic vesicle membranes, its contribution to neurotransmitter release remains unclear. One possibility is that through its association with dynamin it controls the fine tuning of transmitter release. To test this hypothesis, we took advantage of amperometric measurements of quantal catecholamine release from chromaffin cells. First, we showed that synaptophysin and dynamin interact in chromaffin granule-rich fractions and that this interaction relies on the C terminal of synaptophysin. Experimental maneuvers that are predicted to disrupt the association between these two proteins, such as injection of antibodies against dynamin or synaptophysin, or peptides homologous to the C terminal of synaptophysin, increased the quantal size and duration of amperometric spikes. In contrast, the amperometric current that precedes the spike remained unchanged, indicating that synaptophysin/dynamin association does not regulate the initial fusion pore, but it appears to target a later step of exocytosis to control the amount of catecholamines released during a single vesicle fusion event. ER -