Synaptic vesicle cycle: cellular and molecular mechanisms

For synaptic transmission, synaptic vesicles undergo rapid turnover – they are consumed for the transmitter release and subsequently recovered from the plasma membrane via endocytosis. During this rapid turnover, however, synaptic vesicles must maintain their molecular and lipid constituents for their proper functions. Over the last four decades, many experimental approaches and various model systems have been used to study the cellular and molecular mechanisms underlying synaptic vesicle cycle. However, we still lack a complete picture of how this process is mediated. Currently, there are four distinctive models: clathrin-mediated endocytosis, kiss-and-run, bulk endocytosis, and ultrafast endocytosis. The key question in the field is whether there is a unified model for synaptic vesicle recycling or whether specialized mechanisms exist in particular types of synapses or under certain physiological conditions. In addition, the requirement for clathrin and dynamin as pivotal molecules in the process is also still under debate. The purpose of this research topic is to compile both review papers and primary research papers describing the cellular and molecular mechanisms of synaptic vesicle cycle in different model systems. Our goal is to provide neuroscientists an overview of our current understanding of synaptic vesicle cycle.