Cho Sang-Joon, Kelly Marie, Rognlien Katherine T, Cho Jin Ah, Hörber J K Heinrich, Jena Bhanu P
Departments of Physiology and Pharmacology, Wayne State University School of Medicine, 540E Canfield Avenue, Detroit, MI 48201, USA.
Biophys J. 2002 Nov;83(5):2522-7. doi: 10.1016/s0006-3495(02)75263-6.
The process of fusion at the nerve terminal is mediated via a specialized set of proteins in the synaptic vesicles and the presynaptic membrane. Three soluble N-ethylmaleimide-sensitive factor (NSF)-attachment protein receptors (SNAREs) have been implicated in membrane fusion. The structure and arrangement of these SNAREs associated with lipid bilayers were examined using atomic force microscopy. A bilayer electrophysiological setup allowed for measurements of membrane conductance and capacitance. Here we demonstrate that the interaction of these proteins to form a fusion pore is dependent on the presence of t-SNAREs and v-SNARE in opposing bilayers. Addition of purified recombinant v-SNARE to a t-SNARE-reconstituted lipid membrane increased only the size of the globular t-SNARE oligomer without influencing the electrical properties of the membrane. However when t-SNARE vesicles were added to a v-SNARE membrane, SNAREs assembles in a ring pattern and a stepwise increase in capacitance, and increase in conductance were observed. Thus, t- and v-SNAREs are required to reside in opposing bilayers to allow appropriate t-/v-SNARE interactions leading to membrane fusion.
神经末梢处的融合过程是由突触小泡和突触前膜中的一组特殊蛋白质介导的。三种可溶性N - 乙基马来酰亚胺敏感因子（NSF）附着蛋白受体（SNAREs）与膜融合有关。利用原子力显微镜研究了这些与脂质双层相关的SNAREs的结构和排列。双层电生理装置可用于测量膜电导和电容。在这里，我们证明这些蛋白质相互作用形成融合孔取决于相对双层中t - SNAREs和v - SNAREs的存在。将纯化的重组v - SNARE添加到t - SNARE重组脂质膜中，仅增加了球状t - SNARE寡聚体的大小，而不影响膜的电学性质。然而，当将t - SNARE小泡添加到v - SNARE膜中时，SNAREs以环状模式组装，观察到电容逐步增加和电导增加。因此，t - 和v - SNAREs需要存在于相对的双层中，以允许适当的t - /v - SNARE相互作用，从而导致膜融合。
