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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 schiz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuroligin
Neuroligin (NLGN), a type I membrane protein, is a cell adhesion protein on the postsynaptic membrane that mediates the formation and maintenance of synapses between neurons. Neuroligins act as ligands for 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 are implicated in autism and other cognitive disorders. Antibodies in a mother from ... [...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] |
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. The alpha-neurexins contain epidermal growth factor-like (EGF-like Epidermal growth factor (EGF) is a protein that stimulates cell growth and differentiation by binding to its receptor, EGFR. Human EGF is 6-k Da and has 53 amino acid residues and three intramolecular dis ... [...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 be ... [...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 ... [...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 components of the basal lamina (one of the layers of the basement membrane), the protein network foundation for most cells and organs. The laminins are an important and biologically active part of the basal lamina, influencing cell differentiation, migration, and adhesion. Laminins are heterotrimeric proteins with a high molecular mass (~400 to ~900 kDa). They contain 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. Thus, laminin-511 contains α5, β1, and γ1 chains. Fourteen other chain combinations have been identified ''in vivo''. The trimeric proteins intersect to form a cross-like structure that can bind to other cell membrane and extracellular matrix molecules. The three shorter arms are particularly good at binding to other laminin molecules, ... [...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 components of the basal lamina (one of the layers of the basement membrane), the protein network foundation for most cells and organs. The laminins are an important and biologically active part of the basal lamina, influencing cell differentiation, migration, and adhesion. Laminins are heterotrimeric proteins with a high molecular mass (~400 to ~900 kDa). They contain 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. Thus, laminin-511 contains α5, β1, and γ1 chains. Fourteen other chain combinations have been identified ''in vivo''. The trimeric proteins intersect to form a cross-like structure that can bind to other cell membrane and extracellular matrix molecules. The three shorter arms are particularly good at binding to other laminin molecules, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synaptotagmin
Synaptotagmins (SYTs) constitute a family of 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 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 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 synaptotagmins share a similar domain st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synaptic Vesicle
In a neuron, synaptic vesicles (or neurotransmitter vesicles) store various neurotransmitters that are released at the synapse. The release is regulated by a voltage-dependent calcium channel. Vesicles are essential for propagating nerve impulses between neurons and are constantly recreated by the 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% phosphatidylethanolamine, 12% phosphatidylserine, 5% phosphatidylinositol, and 10% chole ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SPEN
Msx2-interacting protein is a protein that in humans is encoded by the ''SPEN'' gene. This gene encodes a hormone inducible transcriptional repressor. Repression of transcription by this gene product can occur through interactions with other repressors, by the recruitment of proteins involved in histone deacetylation, or through sequestration of transcriptional activators. The product of this gene contains a carboxy-terminal domain that permits binding to other corepressor proteins. This domain also permits interaction with members of the NuRD complex, a nucleosome remodeling protein complex that contains deacetylase activity. In addition, this repressor contains several RNA recognition motifs that confer binding to a steroid receptor RNA coactivator; this binding can modulate the activity of both liganded and nonliganded steroid receptors. Interactions SPEN has been shown to interact with HDAC1, SRA1 and Nuclear receptor co-repressor 2 The nuclear receptor co-repressor 2 () is ... [...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. Modern wooden barrels for wine-making are made of French common oak ('' Quercus robur''), white oak ('' Quercus petraea''), American white oak (''Quercus alba''), more exotic is Mizunara Oak all typically have standard sizes: Recently Oregon Oak ( Quercus Garryana) has been used. *"Bordeaux type" , *"Burgundy type" and *"Cognac type" . Modern barrels and casks can also be made of aluminum, stainless steel, and different types of plastic, such as HDPE. Someone who makes barrels is called a "barrel maker" or cooper (coopers also make buckets, vats, tubs, butter churns, hogsheads, firkins, kegs, kilderkins, tierces, rundlets, puncheons, pipes, tuns, butts, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium In Biology
Calcium ions (Ca2+) contribute to the physiology and biochemistry of organisms' cell (biology), cells. They play an important role in signal transduction pathways, where they act as a second messenger, in neurotransmitter release from neurons, in contraction of all muscle cell types, and in fertilization. Many enzymes require calcium ions as a Cofactor (biochemistry), cofactor, including several of the coagulation factors. Extracellular calcium is also important for maintaining the potential difference across excitable cell cell membrane, membranes, as well as proper bone formation. Plasma calcium levels in mammals are tightly regulated, electronic-book electronic- with bone acting as the major mineral storage site. Calcium ions, Ca2+, are released from bone into the bloodstream under controlled conditions. Calcium is transported through the bloodstream as dissolved ions or bound to proteins such as serum albumin. Parathyroid hormone secreted by the parathyroid gland regulates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
