5/16/2023 0 Comments Https vimeo com event 13691Yet, neurotransmission relies on the same SNAREpin zippering mechanism that powers more leisurely and less coherent hormone release and vesicle trafficking within the cell. This is by far the fastest membrane fusion mechanism in nature, as is required for all thought and action. On the structural biochemical mechanism of synaptic neurotransmission in the brainģ Neurotransmitters stored in synaptic vesicles at nerve endings are synchronously released in less than one millisecond after the action potential arrives and calcium ions secondarily enter the pre-synaptic cytoplasm. Recent evidence emerging from synthetic biology – in which we have deliberately altered the adhesive properties of the cisternae to each other and to other organelles – will be presented. Anterograde flow may be mediated by movement of intact cisternae or by vesicle-like carriers. Retrograde flow is mediated by typical transport vesicles. The details of the process are still debated. The cisternae function as if they were plates in a distillation tower in solvent separations. In this process of iterative protein sorting, the same purification process occurs sequentially at each level of the stack, resulting in high overall efficiencies. In this lecture I will develop the idea, first proposed in the 1980s, that the stack carries out a process of protein purification, separating proteins destined to remain in the endoplasmic reticulum (and the Golgi itself) from other locations. The purpose of the stack-like morphology has long been a mystery. The Golgi apparatus plays a central role in the processing and distribution of newly synthesized proteins. On the logic of the Golgi Apparatus – Continuous purification of proteins in the cellĢ All eukaryotic cells have a Golgi apparatus, consisting of a series of stacked membrane-bounded compartments (termed cisternae). Related processes enable communication between cells in the body by releasing and receiving signals from hormones, growth factors, and neurotransmitters. The specificity of the localization of proteins within the cell is generated and maintained by these vesicles enable the cell to self-organize in three dimensions as it grows and divides. Tiny transport vesicles carry highly selected cargoes from one compartment to another providing an internal distribution system not unlike a postal service. This process began in the 1950s with the discovery of numerous specialized membrane-bounded compartments within the cell using the electron microscope, and culminated with the discovery of the ability to reproduce these events in test tube systems. A chain of discoveries over the past half century has revealed the mechanism by which cells organize themselves internally. On the sorting of proteins to compartmentalize the cell – The story of three Nobel Prizes from a modern perspectiveġ This lecture is intended for a broad scientific community as well as the general public.
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