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VAMP1
Vesicle-associated membrane protein 1 (VAMP1) is a protein that in humans is encoded by the ''VAMP1'' gene. Function Synaptobrevins/VAMPs, syntaxins, and the 25-kD synaptosomal-associated protein SNAP25 are the main components of a protein complex involved in the docking and/or fusion of synaptic vesicles with the presynaptic membrane. VAMP1 is a member of the vesicle-associated membrane protein (VAMP)/synaptobrevin family. Multiple alternative splice variants that encode proteins with alternative carboxy ends have been described, but the full-length nature of some variants has not been defined. Clinical significance Homozygous mutations in VAMP1 have been identified in a series of children affected with a form of congenital myasthenic syndrome and similar presynaptic features in these patients and the knock-out A knockout (abbreviated to KO or K.O.) is a fight-ending, winning criterion in several full-contact combat sports, such as boxing, kickboxing, muay thai, mix ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synaptobrevin
Synaptobrevins (''synaptobrevin isotypes 1-2'') are small integral membrane proteins of secretory vesicles with molecular weight of 18 kilodalton (kDa) that are part of the vesicle-associated membrane protein (VAMP) family. Synaptobrevin is one of the SNARE proteins involved in formation of the SNARE complexes. Structure Out of four α-helices of the core SNARE complex one is contributed by synaptobrevin, one by syntaxin, and two by SNAP-25 (in neurons). Function SNARE proteins are the key components of the molecular machinery that drives fusion of membranes in exocytosis. Their function however is subject to fine-tuning by various regulatory proteins collectively referred to as ''SNARE masters''. Classification In the Q/R nomenclature for organizing SNARE proteins, VAMP/synaptobrevin family members are classified as R-SNAREs, so named for the presence of an arginine at a specific location within the primary sequence of the protein (as opposed to the SNAREs of the ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syntaxin
Syntaxins are a family of membrane integrated Q-SNARE proteins participating in exocytosis. Domains Syntaxins possess a single C-terminal transmembrane domain, a SNARE domain (known as H3), and an N-terminal regulatory domain (Habc). Syntaxin 17 may have two transmembrane domains. * The SNARE (H3) domain binds to both synaptobrevin and SNAP-25 forming the core SNARE complex. Formation of this stable SNARE core complex is believed to generate the free energy required to initiate fusion between the vesicle membrane and plasma membrane. * The N-terminal Habc domain is formed by 3 α-helices and when collapsed onto its own H3 helix forms an inactive "closed" syntaxin conformation. This closed conformation of syntaxin is believed to be stabilized by binding of Munc-18 (nSec1), although more recent data suggests that nSec1 may bind to other conformations of syntaxin, as well. The "open" syntaxin conformation is the conformation that is competent to form into SNARE core complexes. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SNAP25
Synaptosomal-Associated Protein, 25kDa (SNAP-25) is a Target Soluble NSF (''N''-ethylmaleimide-sensitive factor) Attachment Protein Receptor (t-SNARE) protein encoded by the ''SNAP25'' gene found on chromosome 20p12.2 in humans. SNAP-25 is a component of the ''trans''-SNARE complex, which accounts for membrane fusion specificity and directly executes fusion by forming a tight complex that brings the synaptic vesicle and plasma membranes together. Structure and function SNAP-25, a Q-SNARE protein, is anchored to the cytosolic face of membranes via palmitoyl side chains covalently bound to cysteine amino acid residues in the central linker domain of the molecule. This means that SNAP-25 does not contain a trans-membrane domain. SNAP-25 has been identified to contribute two α-helices to the SNARE complex, a four-α-helix domain complex. The SNARE complex participates in vesicle fusion, which involves the docking, priming and merging of a vesicle with the cell membrane to in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alternative Splicing
Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be included within or excluded from the final, processed messenger RNA (mRNA) produced from that gene. This means the exons are joined in different combinations, leading to different (alternative) mRNA strands. Consequently, the proteins translated from alternatively spliced mRNAs will contain differences in their amino acid sequence and, often, in their biological functions (see Figure). Biologically relevant alternative splicing occurs as a normal phenomenon in eukaryotes, where it increases the number of proteins that can be encoded by the genome. In humans, it is widely believed that ~95% of multi-exonic genes are alternatively spliced to produce functional alternative products from the same gene but many scientists believe that most o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congenital Myasthenic Syndrome
Congenital myasthenic syndrome (CMS) is an inherited neuromuscular disorder caused by defects of several types at the neuromuscular junction. The effects of the disease are similar to Lambert-Eaton Syndrome and myasthenia gravis, the difference being that CMS is not an autoimmune disorder. There are only 600 known family cases of this disorder and it is estimated that its overall frequency in the human population is 1 in 200,000. Types The types of CMS are classified into three categories: presynaptic, postsynaptic, and synaptic. * ''Presynaptic'' symptoms include brief stops in breathing, weakness of the eye, mouth, and throat muscles. These symptoms often result in double vision and difficulty chewing and swallowing. * ''Postsynaptic'' symptoms in infants include severe muscle weakness, feeding and respiratory problems, and delays in the ability to sit, crawl, and walk. * ''Synaptic'' symptoms include early childhood feeding and respiratory problems, reduced mobility, curva ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
