An Seong J, Almers Wolfhard
Vollum Institute L-474, Oregon Health Sciences University, 3181 Southwest Sam Jackson Park Road, Portland, OR 97201, USA.
Science. 2004 Nov 5;306(5698):1042-6. doi: 10.1126/science.1102559.
Syntaxin, synaptosome-associated protein of 25 kD (SNAP25), and vesicle-associated membrane protein/synaptobrevin are collectively called SNAP receptor (SNARE) proteins, and they catalyze neuronal exocytosis by forming a "core complex." The steps in core complex formation are unknown. Here, we monitored SNARE complex formation in vivo with the use of a fluorescent version of SNAP25. In PC12 cells, we found evidence for a syntaxin-SNAP25 complex that formed with high affinity, required only the amino-terminal SNARE motif of SNAP25, tolerated a mutation that blocks formation of other syntaxin-SNAP25 complexes, and assembled reversibly when Ca2+ entered cells during depolarization. The complex may represent a precursor to the core complex formed during a Ca2+-dependent priming step of exocytosis.
syntaxin、25kD的突触小体相关蛋白（SNAP25）以及囊泡相关膜蛋白/突触融合蛋白统称为SNAP受体（SNARE）蛋白，它们通过形成“核心复合物”来催化神经元胞吐作用。核心复合物形成的步骤尚不清楚。在这里，我们使用荧光版的SNAP25在体内监测SNARE复合物的形成。在PC12细胞中，我们发现了一种 syntaxin-SNAP25复合物形成的证据，该复合物以高亲和力形成，仅需要SNAP25的氨基末端SNARE基序，耐受阻止其他 syntaxin-SNAP25复合物形成的突变，并且在去极化期间Ca2+进入细胞时可逆地组装。该复合物可能代表了在胞吐作用的Ca2+依赖性启动步骤中形成的核心复合物的前体。
