Biology Department Seminar

Mon, Mar 19–Mon, Mar 19

11:45 AM– 1:00 PM

MR-801

Abstract: Chemical synaptic transmission is a unique means by which neurons communicate with their partner cells in the nervous system. Release of neurotransmitter via exocytosis and the endocytosis of synaptic vesicles are the two major presynaptic events of synaptic transmission. Dr. Zhang and his students use the fruit fly (Drosophila melanogaster) as a genetic model organism to investigate the molecular mechanisms of exocytosis and endocytosis. In this presentation, Dr. Zhang will discuss a novel intrinsic mechanism by which SNARE complex assembly regulates the rate of vesicle fusion. Through studies of a mutant syntaxin 1A (one of the SNARE molecules), results from Dr. Zhang's lab indicate that synaptic SNAREs have been evolved to increase the energy barrier for vesicle fusion whereas a conserved SNARE structure promotes Ca2+-independent vesicle fusion along the constitutive secretory pathway. Dr. Zhang will also discuss the role of AP180 in clathrin-mediated recycling of synaptic vesicles. As a clathrin assembly and adaptor protein, AP180 ensures the reformation of uniform synaptic vesicles. Additionally, AP180 appears to play a key role in recovering vesicular proteins during endocytosis. Because SNAREs and AP180 are highly conserved from flies to humans, the findings from Dr. Zhang's research should shed light on synaptic transmission and vesicle trafficking in other organisms, including humans.

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