Synaptic vesicles recycle repeatedly in order to maintain synaptic transmission. We have previously proposed that upon exocytosis the vesicle components persist as clusters, which would be endocytosed as whole units. It has also been proposed that the vesicle components diffuse into the plasma membrane and are then randomly gathered into new vesicles. We found here that while strong stimulation (releasing the entire recycling pool) causes the diffusion of the vesicle marker synaptotagmin out of synaptic boutons, moderate stimulation (releasing approximately 19% of all vesicles) is followed by no measurable diffusion. In agreement with this observation, synaptotagmin molecules labeled with different fluorescently tagged antibodies did not appear to mix upon vesicle recycling, when investigated by subdiffraction resolution stimulated emission depletion (STED) microscopy. Finally, as protein diffusion from vesicles has been mainly observed using molecules tagged with pH-sensitive green fluorescent protein (pHluorin), we have also investigated the membrane patterning of several native and pHluorin-tagged proteins. While the native proteins had a clustered distribution, the GFP-tagged ones were diffused in the plasma membrane. We conclude that synaptic vesicle components intermix little, at least under moderate stimulation, possibly because of the formation of clusters in the plasma membrane. We suggest that several pHluorin-tagged vesicle proteins are less well integrated in clusters.
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http://dx.doi.org/10.1111/j.1600-0854.2010.01058.x | DOI Listing |
Biomolecular condensates are a ubiquitous component of cells, known for their ability to selectively partition and compartmentalize biomolecules without the need for a lipid membrane. Nevertheless, condensates have been shown to interact with lipid membranes in diverse biological processes, such as autophagy and T-cell activation. Since many condensates are known to have a net surface charge density and associated electric potential(s), we hypothesized that they can induce a local membrane potential.
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Leeds Institute of Medical Research, School of Medicine, University of Leeds, St. James University Hospital, Leeds, United Kingdom.
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Department of Epidemiology and Biostatistics (Schulich School of Medicine and Dentistry), Ivey Business School, University of Western Ontario, London, ON, Canada. Electronic address:
Osteoarthritis (OA) is a progressive joint disease that is a frequent reason for pain and physical dysfunction in adults, with enormous social and economic burden. Although ongoing scientific efforts in recent years have made considerable progress towards understanding of the disease's molecular mechanism, the pathogenesis of OA is still not fully known, and its clinical challenge remains. Thus, elucidating molecular events underlying the initiation and progression of OA is crucial for developing novel diagnostic and therapeutic approaches that could facilitate effective clinical management of the illness.
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Vascular Physiology Laboratory, Group of Research and Innovation in Vascular Health, Department of Basic Sciences, Faculty of Basic Sciences, Universidad del Bío-Bío, Chillán, Chile.
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Periodontitis is a multifactorial disease characterized by chronic destruction of the periodontal supporting tissues and is closely associated with the dysbiosis of the plaque biofilm. It is the leading cause of tooth loss in adults. Bacterial extracellular vesicles (BEVs) are released from bacteria, which range in size from 20 to 400 nm.
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