Tae-Young Yoon

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Membrane fusion in eukaryotic cells is thought to be mediated by a highly conserved family of proteins called SNAREs (soluble N-ethyl maleimide sensitive-factor attachment protein receptors). The vesicle-associated v-SNARE engages with its partner t-SNAREs on the target membrane to form a coiled coil that bridges two membranes and facilitates fusion. As(More)
During intracellular membrane trafficking, N-ethylmaleimide-sensitive factor (NSF) and alpha-soluble NSF attachment protein (α-SNAP) disassemble the soluble NSF attachment protein receptor (SNARE) complex for recycling of the SNARE proteins. The molecular mechanism by which NSF disassembles the SNARE complex is largely unknown. Using single-molecule(More)
Ca2+-triggered, synchronized synaptic vesicle fusion underlies interneuronal communication. Complexin is a major binding partner of the SNARE complex, the core fusion machinery at the presynapse. The physiological data on complexin, however, have been at odds with each other, making delineation of its molecular function difficult. Here we report direct(More)
Co-immunoprecipitation (co-IP) has become a standard technique, but its protein-band output provides only static, qualitative information about protein-protein interactions. Here we demonstrate a real-time single-molecule co-IP technique that generates real-time videos of individual protein-protein interactions as they occur in unpurified cell extracts. By(More)
In neurons, synaptotagmin 1 (Syt1) is thought to mediate the fusion of synaptic vesicles with the plasma membrane when presynaptic Ca2+ levels rise. However, in vitro reconstitution experiments have failed to recapitulate key characteristics of Ca2+-triggered membrane fusion. Using an in vitro single-vesicle fusion assay, we found that membrane-anchored(More)
Formation of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex provides mechanical thrust for membrane fusion, but its molecular mechanism is still unclear. Here using magnetic tweezers, we observe mechanical responses of a single neuronal SNARE complex under constant pulling force. Single SNARE complexes may be(More)
Liquid-ordered (L(O)) domains reconstituted in model membranes have provided a useful platform for in vitro studies of the lipid-raft model, in which signalling membrane molecules are thought to be compartmentalized in sphingolipid- and cholesterol-rich domains. These in vitro studies, however, have relied on an uncontrolled phase-separation process that(More)
Munc18, an essential regulatory protein for intracellular membrane fusion mediated by SNAREs, is known for stabilizing the closed conformation of syntaxin through the interaction with the N-terminal Habc domain (amino acids 28-146) of syntaxin. In addition, Munc18 accelerates membrane fusion and its interaction with SNARE core and the N-peptide (amino acids(More)
Lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria, binds Toll-like receptor 4 (TLR4)-MD2 complex and activates innate immune responses. LPS transfer to TLR4-MD2 is catalyzed by both LPS binding protein (LBP) and CD14. To define the sequential molecular interactions underlying this transfer, we reconstituted in(More)
BACKGROUND Androgenetic alopecia (AGA) is a common hair loss disease with genetic predisposition among men and women, and it may commence at any age after puberty. It may significantly affect a variety of psychological and social aspects of one's life and the individual's overall quality of life (QoL). OBJECTIVE This study aimed to investigate the QoL of(More)