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Neurexin
Neurexins (NRXN) are a family of presynaptic cell adhesion proteins that have roles in connecting neurons at the synapse. They are located mostly on the presynaptic membrane and contain a single transmembrane domain. The extracellular domain interacts with proteins in the synaptic cleft, most notably neuroligin, while the intracellular cytoplasmic portion interacts with proteins associated with exocytosis. Neurexin and neuroligin "shake hands," resulting in the connection between the two neurons and the production of a synapse. Neurexins mediate signaling across the synapse, and influence the properties of neural networks by synapse specificity. Neurexins were discovered as receptors for α-latrotoxin, a vertebrate-specific toxin in black widow spider venom that binds to presynaptic receptors and induces massive neurotransmitter release. In humans, alterations in genes encoding neurexins are implicated in autism and other cognitive diseases, such as Tourette syndrome and sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuroligin
Neuroligin (NLGN), a Transmembrane protein, type I membrane protein, is a Cell adhesion molecule, cell adhesion protein on the Chemical synapse#Structure, postsynaptic membrane that mediates the formation and maintenance of synapses between neurons. Neuroligins act as ligands for Neurexin, β-neurexins, which are cell adhesion proteins located presynaptically. Neuroligin and β-neurexin "shake hands", resulting in the connection between two neurons and the production of a synapse. Neuroligins also affect the properties of neural networks by specifying synaptic functions, and they mediate signalling by recruiting and stabilizing key synaptic components. Neuroligins interact with other postsynaptic proteins to localize neurotransmitter receptors and channels in the postsynaptic density as the cell matures. Additionally, neuroligins are expressed in human peripheral tissues and have been found to play a role in angiogenesis. In humans, alterations in genes encoding neuroligins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NRXN1
Neurexin-1-alpha is a protein that in humans is encoded by the ''NRXN1'' gene. Neurexins are a family of proteins that function in the vertebrate nervous system as cell adhesion molecules and receptors. They are encoded by several unlinked genes of which two, NRXN1 and NRXN3, are among the largest known human genes. Three of the genes (NRXN1-3) utilize two alternate promoters and include numerous alternatively spliced exons to generate thousands of distinct mRNA transcripts and protein isoforms. The majority of transcripts are produced from the upstream promoter and encode alpha-neurexin isoforms; a much smaller number of transcripts are produced from the downstream promoter and encode beta-neurexin isoforms. The alpha-neurexins contain epidermal growth factor-like (EGF-like) sequences and laminin G domains, and have been shown to interact with neurexophilins. The beta-neurexins lack EGF-like sequences and contain fewer laminin G domains than alpha-neurexins. Function Neurexins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synaptogenesis
Synaptogenesis is the formation of synapses between neurons in the nervous system. Although it occurs throughout a healthy person's lifespan, an explosion of synapse formation occurs during early brain development, known as exuberant synaptogenesis. Synaptogenesis is particularly important during an individual's critical period, during which there is a certain degree of synaptic pruning due to competition for neural growth factors by neurons and synapses. Processes that are not used, or inhibited during their critical period will fail to develop normally later on in life. Exuberant synaptogenesis Brain growth and development begins during gestation and into the postnatal period. Brain development can be divided into stages including: neurogenesis, differentiation, proliferation, migration, synaptogenesis, gliogenesis and myelination, and apoptosis and synaptic pruning. Synaptogenesis occurs in the third trimester during gestation as well as the first two years postnatal. Dur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NRXN2
Neurexin-2-alpha is a protein that in humans is encoded by the ''NRXN2'' gene. Neurexins are a family of proteins that function in the vertebrate nervous system as cell adhesion molecules and receptors. They are encoded by several unlinked genes of which two, NRXN1 and NRXN3, are among the largest known human genes. Three of the genes (NRXN1-3) utilize two alternate promoters and include numerous alternatively spliced exons to generate thousands of distinct mRNA transcripts and protein isoforms. The majority of transcripts are produced from the upstream promoter and encode alpha-neurexin isoforms; a much smaller number of transcripts are produced from the downstream promoter and encode beta-neurexin isoforms A protein isoform, or "protein variant", is a member of a set of highly similar proteins that originate from a single gene and are the result of genetic differences. While many perform the same or similar biological roles, some isoforms have uniqu .... The alpha-neurexins co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NRXN3
Neurexin-3-alpha is a protein that in humans is encoded by the ''NRXN3'' gene. Neurexins are a family of proteins that function in the vertebrate nervous system as cell adhesion molecules and receptors. They are encoded by several unlinked genes of which two, NRXN1 and NRXN3, are among the largest known human genes. Three of the genes (NRXN1-3) utilize two alternate promoters and include numerous alternatively spliced exons to generate thousands of distinct mRNA transcripts and protein isoforms. The majority of transcripts are produced from the upstream promoter and encode alpha-neurexin isoforms; a much smaller number of transcripts are produced from the downstream promoter and encode beta-neurexin isoforms. The alpha-neurexins contain epidermal growth factor-like (EGF-like) sequences and laminin G domains, and have been shown to interact with neurexophilins. The beta-neurexins lack EGF-like sequences and contain fewer laminin G domains than alpha-neurexins. NRXN3 is thought to b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
α-latrotoxin
A latrotoxin is a high-molecular mass neurotoxin found in the venom of spiders of the genus ''Latrodectus'' (widow spiders) as well as at least one species of another genus in the same family, ''Steatoda nobilis''. Latrotoxins are the main active components of the venom and are responsible for the symptoms of latrodectism. The following latrotoxins have been described: five insecticidal toxins, termed α, β, γ, δ and ε-latroinsectotoxins, one vertebrate-specific neurotoxin, alpha-latrotoxin, and one toxin affecting crustaceans, α-latrocrustatoxin. α-latrotoxin The best-studied latrotoxin is alpha-latrotoxin, which acts presynaptically to release neurotransmitters (including acetylcholine) from sensory and motor neurons, as well as on endocrine cells (to release insulin, for example). It is a ~130 kDa protein that exists mainly in its dimerized or tetramerized forms. α-latrotoxin (α-LTX) can naturally be found in widow spiders of the genus ''Latrodectus''. The most w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laminin
Laminins are a family of glycoproteins of the extracellular matrix of all animals. They are major constituents of the basement membrane, namely the basal lamina (the protein network foundation for most cells and organs). Laminins are vital to biological activity, influencing cell differentiation, migration, and adhesion. Laminins are heterotrimeric proteins with a high molecular mass (~400 to ~900 kDa) and possess three different chains (α, β, and γ) encoded by five, four, and three paralogous genes in humans, respectively. The laminin molecules are named according to their chain composition, e.g. laminin-511 contains α5, β1, and γ1 chains. Fourteen other chain combinations have been identified ''in vivo''. The trimeric proteins intersect, composing a cruciform structure that is able to bind to other molecules of the extracellular matrix and cell membrane. The three short arms have an affinity for binding to other laminin molecules, conducing sheet formation. The long ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synaptotagmin
Synaptotagmins (SYTs) constitute a family of cell membrane, membrane-trafficking proteins that are characterized by an N-terminal transmembrane region (TMR), a variable linker, and two C-terminal C2 domains - C2A and C2B. There are 17 Protein isoform, isoforms in the mammalian synaptotagmin family. There are several C2-domain containing protein families that are related to synaptotagmins, including transmembrane (Ferlins, Extended-Synaptotagmin (E-Syt) membrane proteins, and MCTPs) and soluble (RIMS1 and RIMS2, UNC13D, synaptotagmin-related proteins and B/K) proteins. The family includes SYT1, synaptotagmin 1, a Ca2+ sensor in the membrane of the pre-synaptic axon terminal, coded by gene SYT1. Functions Based on their brain/endocrine distribution and biochemical properties, in particular C2 domains of certain synaptotagmins bound to calcium, synaptotagmins were proposed to function as calcium sensors in the regulation of neurotransmitter release and hormone secretion. Although syna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synaptic Vesicle
In a neuron, synaptic vesicles (or neurotransmitter vesicles) store various neurotransmitters that are exocytosis, released at the chemical synapse, synapse. The release is regulated by a voltage-dependent calcium channel. Vesicle (biology), Vesicles are essential for propagating nerve impulses between neurons and are constantly recreated by the cell (biology), cell. The area in the axon that holds groups of vesicles is an axon terminal or "terminal bouton". Up to 130 vesicles can be released per bouton over a ten-minute period of stimulation at 0.2 Hz. In the visual cortex of the human brain, synaptic vesicles have an average diameter of 39.5 nanometers (nm) with a standard deviation of 5.1 nm. Structure Synaptic vesicles are relatively simple because only a limited number of proteins fit into a sphere of 40 nm diameter. Purified vesicles have a protein:phospholipid ratio of 1:3 with a lipid composition of 40% phosphatidylcholine, 32% phosphatidylethanola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SPEN
Spen may refer to: *SPEN, human gene *Spen, West Yorkshire, a List of United Kingdom locations: Sow-Stao#Sp, location in England *River Spen, river in West Yorkshire, England, the United Kingdom *SS Spen, SS ''Spen'', British steamship built in 1908 *Spen Whittaker (1871–1910), English football manager *ScottishPower#Energy Networks, SP Energy Networks, the energy networks arm of Scottish Power See also *S Pen, stylus pen for Samsung smartphones {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CASK
A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids, usually alcoholic beverages; a small barrel or cask is known as a keg. Barrels have a variety of uses, including storage of liquids such as water, oil, and alcohol. They are also employed to hold maturing beverages such as wine, cognac, armagnac, sherry, port, whiskey, beer, arrack, and sake. Other commodities once stored in wooden casks include gunpowder, meat, fish, paint, honey, nails, and tallow. Modern wooden barrels for wine-making are made of English oak (''Quercus robur''), white oak (''Quercus petraea''), American white oak (''Quercus alba''), more exotic is mizunara oak ('' Quercus crispula''), and recently Oregon oak ('' Quercus garryana'') has been used. Someone who makes traditional wooden barrels is called a coope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
