Jena Bhanu P
Wayne State University School of Medicine, Department of Physiology, Detroit, MI, USA.
J Mol Struct. 2014 Sep 5;1073:187-195. doi: 10.1016/j.molstruc.2014.04.055.
Cup-shaped secretory portals at the cell plasma membrane called mediate secretion from cells. Membrane bound secretory vesicles transiently dock and fuse at the cytosolic compartment of the porosome base to expel intravesicular contents to the outside during cell secretion. In the past decade, the structure, isolation, composition, and functional reconstitution of the neuronal porosome complex has been accomplished providing a molecular understanding of its structure-function. Neuronal porosomes are 15 nm cup-shaped lipoprotein structures composed of nearly 40 proteins. Being a membrane-associated supramolecular complex has precluded determination of the atomic structure of the porosome. However recent studies using small-angle X-ray solution scattering (SAXS), provide at sub-nanometer resolution, the native 3D structure of the neuronal porosome complex associated with docked synaptic vesicle at the nerve terminal. Additionally, results from the SAXS study and earlier studies using atomic force microscopy, provide the possible molecular mechanism involved in porosome-mediated neurotransmitter release at the nerve terminal.
细胞膜上称为孔体的杯状分泌通道介导细胞分泌。膜结合分泌囊泡在孔体基部的胞质区短暂对接并融合，以便在细胞分泌过程中将囊泡内的内容物排出到细胞外。在过去十年中，神经元孔体复合物的结构、分离、组成和功能重建已完成，从而对其结构功能有了分子层面的理解。神经元孔体是由近40种蛋白质组成的15纳米杯状脂蛋白结构。作为一种膜相关超分子复合物，难以确定孔体的原子结构。然而，最近使用小角X射线溶液散射（SAXS）的研究，在亚纳米分辨率下提供了与神经末梢对接的突触囊泡相关的神经元孔体复合物的天然三维结构。此外，SAXS研究结果以及早期使用原子力显微镜的研究，提供了神经末梢孔体介导神经递质释放可能涉及的分子机制。
