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The Japanese Dental Science Review May 2017Matrix vesicle-mediated mineralization is an orchestrated sequence of ultrastructural and biochemical events that lead to crystal nucleation and growth. The influx of... (Review)
Review
Matrix vesicle-mediated mineralization is an orchestrated sequence of ultrastructural and biochemical events that lead to crystal nucleation and growth. The influx of phosphate ions into the matrix vesicle is mediated by several proteins such as TNAP, ENPP1, Pit1, annexin and so forth. The catalytic activity of ENPP1 generates pyrophosphate (PPi) using extracellular ATPs as a substrate, and the resultant PPi prevents crystal overgrowth. However, TNAP hydrolyzes PPi into phosphate ion monomers, which are then transported into the matrix vesicle through Pit1. Accumulation of Ca and PO inside matrix vesicles then induces crystalline nucleation, with calcium phosphate crystals budding off radially, puncturing the matrix vesicle's membrane and finally growing out of it to form mineralized nodules.
PubMed: 28479934
DOI: 10.1016/j.jdsr.2016.09.002 -
The Neuroscientist : a Review Journal... Oct 2016Ca(2+)-dependent synaptic vesicle recycling is essential for structural homeostasis of synapses and maintenance of neurotransmission. Although, the executive role of... (Review)
Review
Ca(2+)-dependent synaptic vesicle recycling is essential for structural homeostasis of synapses and maintenance of neurotransmission. Although, the executive role of intrasynaptic Ca(2+) transients in synaptic vesicle exocytosis is well established, identifying the exact role of Ca(2+) in endocytosis has been difficult. In some studies, Ca(2+) has been suggested as an essential trigger required to initiate synaptic vesicle retrieval, whereas others manipulating synaptic Ca(2+) concentrations reported a modulatory role for Ca(2+) leading to inhibition or acceleration of endocytosis. Molecular studies of synaptic vesicle endocytosis, on the other hand, have consistently focused on the roles of Ca(2+)-calmodulin dependent phosphatase calcineurin and synaptic vesicle protein synaptotagmin as potential Ca(2+) sensors for endocytosis. Most studies probing the role of Ca(2+) in endocytosis have relied on measurements of synaptic vesicle retrieval after strong stimulation. Strong stimulation paradigms elicit fusion and retrieval of multiple synaptic vesicles and therefore can be affected by several factors besides the kinetics and duration of Ca(2+) signals that include the number of exocytosed vesicles and accumulation of released neurotransmitters thus altering fusion and retrieval processes indirectly via retrograde signaling. Studies monitoring single synaptic vesicle endocytosis may help resolve this conundrum as in these settings the impact of Ca(2+) on synaptic fusion probability can be uncoupled from its putative role on synaptic vesicle retrieval. Future experiments using these single vesicle approaches will help dissect the specific role(s) of Ca(2+) and its sensors in synaptic vesicle endocytosis.
Topics: Animals; Calcium; Endocytosis; Exocytosis; Humans; Secretory Vesicles; Synapses; Synaptic Vesicles
PubMed: 25998187
DOI: 10.1177/1073858415588265 -
Cell and Tissue Research Nov 2006The release of neurotransmitter from synaptic vesicles represents the final event by which presynapses send their chemical signal to the receiving postsynapses. Prior to... (Review)
Review
The release of neurotransmitter from synaptic vesicles represents the final event by which presynapses send their chemical signal to the receiving postsynapses. Prior to fusion, synaptic vesicles undergo a series of maturation events, most notably the membrane-delimited docking and priming steps. Physiological and optical experiments with high-time resolution have allowed the distinction of vesicles in different maturation states with respect to fusion, the so-called vesicle pools. In this review, we define the various vesicle pools and discuss pathways leading into and out of these pools. We also provide an overview of an array of proteins that have been identified or are speculated to play a role in the transition between the various vesicle pools.
Topics: Animals; Humans; Nerve Tissue Proteins; Neurotransmitter Agents; Presynaptic Terminals; Synaptic Transmission; Synaptic Vesicles; Vesicular Transport Proteins
PubMed: 16819626
DOI: 10.1007/s00441-006-0243-z -
Annual Review of Physiology 1998The ins and outs of the synaptic vesicle cycle are being examined in increasing detail with diverse investigative tools in a variety of cell types, particularly those... (Review)
Review
The ins and outs of the synaptic vesicle cycle are being examined in increasing detail with diverse investigative tools in a variety of cell types, particularly those with large granules. The cycle begins with the opening of a fusion pore that connects the vesicle lumen to the extracellular fluid. Sensitive electrophysiological techniques reveal the often-stuttering behavior of single pores in non-neuronal cells, through which small molecules trickle until the fusion pore expands and the remaining contents erupt from the vesicle. The granule membranes are then retrieved by multiple processes that appear to act in parallel and that are distinguished from each other kinetically and ultrastructurally. Following endocytosis, synaptic vesicles are then shuttled back into the vesicle pool, where they briefly mix with other vesicles, become immobilized, and remain gelled with their neighbors, even while moving en masse again to the presynaptic membrane as a prelude for another round of exocytosis.
Topics: Animals; Endocytosis; Humans; Receptors, Presynaptic; Synaptic Vesicles
PubMed: 9558468
DOI: 10.1146/annurev.physiol.60.1.347 -
Journal of Neurochemistry Jun 2007Synaptic vesicles are key organelles in neurotransmission. Vesicle integral or membrane-associated proteins mediate the various functions the organelle fulfills during... (Review)
Review
Synaptic vesicles are key organelles in neurotransmission. Vesicle integral or membrane-associated proteins mediate the various functions the organelle fulfills during its life cycle. These include organelle transport, interaction with the nerve terminal cytoskeleton, uptake and storage of low molecular weight constituents, and the regulated interaction with the pre-synaptic plasma membrane during exo- and endocytosis. Within the past two decades, converging work from several laboratories resulted in the molecular and functional characterization of the proteinaceous inventory of the synaptic vesicle compartment. However, up until recently and due to technical difficulties, it was impossible to screen the entire organelle thoroughly. Recent advances in membrane protein identification and mass spectrometry (MS) have dramatically promoted this field. A comparison of different techniques for elucidating the proteinaceous composition of synaptic vesicles revealed numerous overlaps but also remarkable differences in the protein constituents of the synaptic vesicle compartment, indicating that several protein separation techniques in combination with differing MS approaches are required to identify and characterize the synaptic vesicle proteome. This review highlights the power of various gel separation techniques and MS analyses for the characterization of the proteome of highly purified synaptic vesicles. Furthermore, the newly detected protein assignments to synaptic vesicles, especially those proteins which are new to the inventory of the synaptic vesicle proteome, are critically discussed.
Topics: Animals; Clathrin-Coated Vesicles; GTP-Binding Proteins; Humans; Membrane Proteins; Nerve Tissue Proteins; Neurotransmitter Transport Proteins; Proteasome Endopeptidase Complex; Protein Isoforms; Proteome; Synaptic Vesicles
PubMed: 17355250
DOI: 10.1111/j.1471-4159.2007.04453.x -
Traffic (Copenhagen, Denmark) Apr 2015Neuronal communication relies on chemical synaptic transmission for information transfer and processing. Chemical neurotransmission is initiated by synaptic vesicle... (Review)
Review
Neuronal communication relies on chemical synaptic transmission for information transfer and processing. Chemical neurotransmission is initiated by synaptic vesicle fusion with the presynaptic active zone resulting in release of neurotransmitters. Classical models have assumed that all synaptic vesicles within a synapse have the same potential to fuse under different functional contexts. In this model, functional differences among synaptic vesicle populations are ascribed to their spatial distribution in the synapse with respect to the active zone. Emerging evidence suggests, however, that synaptic vesicles are not a homogenous population of organelles, and they possess intrinsic molecular differences and differential interaction partners. Recent studies have reported a diverse array of synaptic molecules that selectively regulate synaptic vesicles' ability to fuse synchronously and asynchronously in response to action potentials or spontaneously irrespective of action potentials. Here we discuss these molecular mediators of vesicle pool heterogeneity that are found on the synaptic vesicle membrane, on the presynaptic plasma membrane, or within the cytosol and consider some of the functional consequences of this diversity. This emerging molecular framework presents novel avenues to probe synaptic function and uncover how synaptic vesicle pools impact neuronal signaling.
Topics: Action Potentials; Animals; Humans; Neurotransmitter Agents; Synaptic Membranes; Synaptic Transmission; Synaptic Vesicles
PubMed: 25620674
DOI: 10.1111/tra.12262 -
Journal of Biosciences 2022Eukaryotic cells use small membrane-enclosed vesicles to transport molecular cargo between intracellular compartments. Interactions between molecules on vesicles and...
Eukaryotic cells use small membrane-enclosed vesicles to transport molecular cargo between intracellular compartments. Interactions between molecules on vesicles and compartments determine the source and target compartment of each vesicle type. The set of compartment and vesicle types in a cell define the nodes and edges of a transport graph known as the vesicle traffic network. The transmembrane SNARE proteins that regulate vesicle fusion to target compartments travel in cycles through the transport graph, but the paths they follow must be tightly regulated to avoid aberrant vesicle fusion. Here we use graph-theoretic ideas to understand how such molecular constraints place constraints on the structure of the transport graph. We identify edge connectivity (the minimum number of edges that must be removed to disconnect a graph) as a key determinant that separates allowed and disallowed types of transport graphs. As we increase the flexibility of molecular regulation, the required edge connectivity decreases, so more types of vesicle transport graphs are allowed. These results can be used to aid the discovery of new modes of molecular regulation and new vesicle traffic pathways.
Topics: Computational Biology; Computer Graphics; Eukaryotic Cells; SNARE Proteins; Transport Vesicles
PubMed: 35092413
DOI: No ID Found -
FEBS Letters Nov 2018In presynaptic nerve terminals, synaptic vesicles are recycled locally via an evolutionarily conserved process that ensures maintenance of neurotransmission as well as... (Review)
Review
In presynaptic nerve terminals, synaptic vesicles are recycled locally via an evolutionarily conserved process that ensures maintenance of neurotransmission as well as structural integrity of synapses. Temperature is a key environmental factor that impacts critical steps involved in fusion, endocytosis and transport in different vesicle trafficking pathways. In neurons, temperature changes have been shown to impact synaptic vesicle recycling and synaptic efficacy. But contrary to non-neuronal systems, the temperature dependence of the steps involved in fusion, endocytosis and recycling of synaptic vesicles in presynaptic terminals is not completely understood, and the existing data remain highly debated. In this Review, we discuss the implications of biophysical, biochemical and functional findings on temperature dependence of membrane retrieval in multiple systems. We propose that systematic investigation of the temperature dependence of the presynaptic vesicle trafficking process can provide novel insight into poorly understood mechanisms that govern synaptic vesicle trafficking under diverse physiological conditions.
Topics: Animals; Endocytosis; Humans; Neurons; Presynaptic Terminals; Synapses; Synaptic Transmission; Synaptic Vesicles; Temperature; Time Factors
PubMed: 30311950
DOI: 10.1002/1873-3468.13268 -
Advances in Experimental Medicine and... 2020Primary diseases of the seminal vesicles (SV) are very rare entities.Nonneoplastic lesions of the seminal vesicles include amyloidosis, inflammation, calcification and...
Primary diseases of the seminal vesicles (SV) are very rare entities.Nonneoplastic lesions of the seminal vesicles include amyloidosis, inflammation, calcification and calculi, radiation-induced changes, and basal cell proliferation.Seminal vesicles are frequently involved by tumors originating elsewhere, in particular by prostatic adenocarcinoma, urothelial carcinoma, and rectal adenocarcinoma. On the contrary, primary tumors of the seminal vesicles are rare. Among these, the most common is seminal vesicle adenocarcinoma. To date, less than 100 cases have been reported in literature. Morphologically, primary SV adenocarcinoma is described as a papillary or sheetlike growth architecture, with trabecular and glandular patterns, composed by hobnail tumor cells, frequently with mucinous differentiation. On the contrary, mesenchymal tumors include benign lesions such as leiomyoma, schwannoma, fibroma, paraganglioma, solitary fibrous tumor, cystadenoma, and mixed epithelial and stromal tumors (MEST).Cystadenoma is a rare benign tumor, while MESTs are biphasic tumors with stromal and benign epithelial components. Histological features such as stromal atypia, mitotic activity, nuclear pleomorphism, and tumor necrosis distinct MEST in low-, intermediate-, and high-grade tumors.In recent years, multiple studies reported a link between tumorigenesis and tumor microenvironment. In this regard, the molecular mechanisms connecting prostate cancer (PCa) progression and the host microenvironment have been described and include extracellular matrix (ECM), myofibroblasts, cancer-associated fibroblasts (CAFs), neuroendocrine cells, adipose tissue, and the immune-modulatory cells. Of note, only one study evaluated the influence of seminal vesicle's tumor microenvironment (SVME) on prostate cancer cells so far. Besides, in vivo experiments in NOD/SCID mice clarified the influence of SVME on PCa progression. As such, the injection of PC3 cells into the prostate or the SV resulted in different tumor aggressiveness, and the incidence of retroperitoneal lymph node metastases was significantly higher in mice models receiving SV injection. These findings demonstrated that SVs (rather than the prostate) offer a stimulating tumor microenvironment for growth and invasion of prostate cancer cells.
Topics: Animals; Carcinoma, Transitional Cell; Humans; Male; Mice; Mice, Inbred NOD; Mice, SCID; Prostatic Neoplasms; Seminal Vesicles; Tumor Microenvironment; Urinary Bladder Neoplasms
PubMed: 34185301
DOI: 10.1007/978-3-030-59038-3_19 -
The Neuroscientist : a Review Journal... Feb 2006Presynaptic nerve terminals are exquisite vesicle trafficking machines. Neurotransmission is sustained by constant recycling of a handful of vesicles. Therefore, the... (Review)
Review
Presynaptic nerve terminals are exquisite vesicle trafficking machines. Neurotransmission is sustained by constant recycling of a handful of vesicles. Therefore, the rate and the pathway of vesicle trafficking can critically determine synaptic efficacy during activity. However, it is yet unclear whether synaptic vesicle recycling becomes rate limiting on a rapid time scale during physiologically relevant forms of activity in the brain. Several forms of synaptic plasticity arise from persistent alterations in the dynamics of vesicle trafficking in presynaptic terminals. What makes presynaptic forms of plasticity particularly interesting is that they not only increase or decrease the amplitude of synaptic responses but also cause frequency-dependent changes in neurotransmission. In this manner, plasticity can alter the information coding in neural circuits beyond simple scaling of synaptic responses. However, studying the synaptic vesicle cycle beyond exocytosis and endocytosis has been difficult. In the past decade, several methods have been developed to infer vesicles' trajectory during their cycle in the synapse. Nevertheless, several questions remain. A better understanding of the role of synaptic vesicle trafficking in neurotransmission will require novel approaches that either combine existing methods or the development of new methods to trace vesicles during their cycle. Recent evidence suggests that various presynaptic proteins involved in the synaptic function and homeostasis are either mutated or altered in their expression in several neurological and psychiatric disorders. Therefore, elucidation of the mechanisms that underlie the synaptic vesicle cycle may reveal novel therapeutic targets for brain disorders.
Topics: Animals; Humans; Neuronal Plasticity; Neurotransmitter Agents; Synapses; Synaptic Vesicles
PubMed: 16394193
DOI: 10.1177/1073858405281852