Although several proteins have been implicated in secretory vesicle tethering, the identity and mechanical properties of the components forming the physical vesicle-plasma membrane link remain unknown. Here we present the first experimental measurements of nanomechanical properties of secretory vesicle-plasma membrane tethers using combined AFM force clamp and TIRF microscopy on membrane sheets...

At the heart of synaptic transmission resides the synaptic vesicle cycle – a membrane trafficking pathway in which small membrane-bound vesicles mediate the release of neurotransmitter from presynaptic terminals. The cycle resembles general membrane trafficking and has three phases: vesicle filling, release and recycling. During filling, neurotransmitter is loaded into vesicles via vesicular ne...

methods mycobacterium tuberculosis standard strain crbip7.11 was cultured at 37°c in loewenstein johnson (lj) media for 3-4 weeks. to confirm the species, standard microbiological and biochemical tests were performed. after preparation of membrane vesicles, the amount of protein in membrane vesicles was measured by sds-page and nanodrop. to analyze the integrity and morphology of extracellular ...

Unconventional protein export/secretion (UPE/UPS), in contrast to the classical ER-Golgi-dependent of proteins with a leader sequence (signal peptide), employs multiple means release leaderless cargoes (and some special cases, sequence) extracellular space. By far, two major types UPE have been classified, vesicle-independent and vesicle-dependent UPE. In former, can directly tr...

Secretory vesicles are neutrophil intracellular storage granules formed by endocytosis. Understanding the functional consequences of secretory vesicle exocytosis requires knowledge of their membrane proteins. The current study was designed to use proteomic technologies to develop a more complete catalog of secretory vesicle membrane proteins and to compare the proteomes of secretory vesicle and...

At an initial step during synaptic vesicle recycling, dynamin and adaptor proteins mediate the endocytosis of synaptic vesicle components from the plasma membrane. StonedA and stonedB, novel synaptic proteins encoded by a single Drosophila gene, have predicted structural similarities to adaptors and other proteins implicated in endocytosis. Here, we test possible roles of the stoned proteins in...

After synaptic vesicle fusion, vesicle proteins must be segregated from plasma membrane proteins and recycled to maintain a functional vesicle pool. We monitored the distribution of synaptobrevin, a vesicle protein required for exocytosis, in Caenorhabditis elegans motor neurons by using a pH-sensitive synaptobrevin GFP fusion protein, synaptopHluorin. We estimated that 30% of synaptobrevin was...

The classical model of secretory vesicle recycling after exocytosis involves the retrieval of membrane (the omega figure) at a different site. An alternative model involves secretory vesicles transiently fusing with the plasma membrane (the 'kiss and run' mechanism) [1,2]. No continuous observation of the fate of a single secretory vesicle after exocytosis has been made to date. To study the dy...

Syntaxin is a cytoplasmically oriented plasma membrane protein and VAMP (vesicle-associated membrane protein; synaptobrevin) is a protein associated with the secretory vesicle membrane. These two proteins form part of a complex which is thought to mediate the fusion of plasma and vesicle membranes during exocytosis. This paper reports the identification of syntaxin and VAMP homologues in sea ur...

Synaptic vesicles have a high sterol content, but the importance of vesicular sterols during vesicle recycling is unclear. We used the Drosophila temperature-sensitive dynamin mutant, shibire-ts1, to block endocytosis of recycling synaptic vesicles and to trap them reversibly at the plasma membrane where they were accessible to sterol extraction. Depletion of sterols from trapped vesicles preve...