Stoichiomeric biology and life cycle of the SNAREs

点击翻译按钮获取中文摘要

The exocytotic SNAREs are clustered in membranes, a concept which is common for essentially all membrane proteins investigated to date. This constitutes new challenges for biological sciences: first, to unravel the roles and dynamics of free versus clustered proteins and second, to understand both the flow into the cluster system and the flow out of the cluster system. Here, we propose to combine the expertise of our laboratories to study the life-cycle of SNAREs, the relative proportions between different SNARE-populations and basics of SNARE protein clustering/stoichiometry in the synapse. We will determine the numbers of SNAREs in the synapse, their clustering, as well as the exchange between clustered and free proteins, as well as the trafficking of SNAREs into and out of the synapse. We will determine the fraction of SNAREs specifically required for synapse function (the active pool), and we will assess whether the clusters are functional units directly involved in exocytosis. Finally, we will test whether the clusters represent reserve pools of molecules, or whether they have a signaling function, for example in concentrating accessory proteins. We expect that unraveling the stoichiometric biology and the life cycle of SNAREs will greatly advance our understanding of synaptic function. More importantly, we will obtain for the first time an understanding of the functional organization of a set of proteins in biological membranes.