Department of Medical Cell Biology, Uppsala University, Uppsala 75123, Sweden.
Proc Natl Acad Sci U S A. 2010 Nov 30;107(48):20804-9. doi: 10.1073/pnas.1014823107. Epub 2010 Nov 12.
Syntaxin resides in the plasma membrane, where it helps to catalyze membrane fusion during exocytosis. The protein also forms clusters in cell-free and granule-free plasma-membrane sheets. We imaged the interaction between syntaxin and single secretory granules by two-color total internal reflection microscopy in PC12 cells. Syntaxin-GFP assembled in clusters at sites where single granules had docked at the plasma membrane. Clusters were intermittently present at granule sites, as syntaxin molecules assembled and disassembled in a coordinated fashion. Recruitment to granules required the N-terminal domain of syntaxin, but not the entry of syntaxin into SNARE complexes. Clusters facilitated exocytosis and disassembled once exocytosis was complete. Syntaxin cluster formation defines an intermediate step in exocytosis.
突触融合蛋白位于质膜中，在胞吐过程中帮助催化膜融合。该蛋白还在无细胞和无颗粒的质膜片中形成簇。我们通过双色全内反射显微镜在 PC12 细胞中对突触融合蛋白与单个分泌颗粒之间的相互作用进行了成像。突触融合蛋白 - GFP 在单个颗粒与质膜对接的部位聚集形成簇。簇在颗粒部位间歇性存在，因为突触融合蛋白分子以协调的方式组装和解组装。募集到颗粒需要突触融合蛋白的 N 端结构域，但不需要其进入 SNARE 复合物。簇促进了胞吐作用，并且一旦胞吐作用完成，就会解组装。突触融合蛋白簇的形成定义了胞吐作用的中间步骤。
