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TRIM25
Tripartite motif-containing protein 25 is a protein that in humans is encoded by the ''TRIM25'' gene. Function The protein encoded by this gene is a member of the tripartite motif (TRIM) family grouping more than 70 TRIMs. TRIM proteins primarily function as ubiquitin ligases that regulate the innate response to infection. TRIM25 localizes to the cytoplasm. The presence of potential DNA-binding and dimerization-transactivation domains suggests that this protein may act as a transcription factor, similar to several other members of the TRIM family. Expression of the gene is upregulated in response to estrogen, and it is thought to mediate estrogen actions in breast cancer as a primary response gene. Domain Architecture TRIM25 has an N-terminal RING domain, followed by a B-box type 1 domain, a B-box type 2 domain, a coiled-coil domain (CCD) and a C-terminal SPRY domain. The RING domain coordinates two zinc atoms and is essential for recruiting ubiquitin-conjugating enzymes. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ubiquitination
Ubiquitin is a small (8.6 kDa) regulatory protein found in most tissues of eukaryotic organisms, i.e., it is found ''ubiquitously''. It was discovered in 1975 by Gideon Goldstein and further characterized throughout the late 1970s and 1980s. Four genes in the human genome code for ubiquitin: UBB, UBC, UBA52 and RPS27A. The addition of ubiquitin to a substrate protein is called ubiquitylation (or, alternatively, ubiquitination or ubiquitinylation). Ubiquitylation affects proteins in many ways: it can mark them for degradation via the proteasome, alter their cellular location, affect their activity, and promote or prevent protein interactions. Ubiquitylation involves three main steps: activation, conjugation, and ligation, performed by ubiquitin-activating enzymes (E1s), ubiquitin-conjugating enzymes (E2s), and ubiquitin ligases (E3s), respectively. The result of this sequential cascade is to bind ubiquitin to lysine residues on the protein substrate via an isopeptide bond, cy ... [...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] |
Ubiquitin Ligases
A ubiquitin ligase (also called an E3 ubiquitin ligase) is a protein that recruits an E2 ubiquitin-conjugating enzyme that has been loaded with ubiquitin, recognizes a protein substrate, and assists or directly catalyzes the transfer of ubiquitin from the E2 to the protein substrate. In simple and more general terms, the ligase enables movement of ubiquitin from a ubiquitin carrier to another thing (the substrate) by some mechanism. The ubiquitin, once it reaches its destination, ends up being attached by an isopeptide bond to a lysine residue, which is part of the target protein. E3 ligases interact with both the target protein and the E2 enzyme, and so impart substrate specificity to the E2. Commonly, E3s polyubiquitinate their substrate with Lys48-linked chains of ubiquitin, targeting the substrate for destruction by the proteasome. However, many other types of linkages are possible and alter a protein's activity, interactions, or localization. Ubiquitination by E3 ligases r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ubiquitin-conjugating Enzyme
Ubiquitin-conjugating enzymes, also known as E2 enzymes and more rarely as ''ubiquitin-carrier enzymes'', perform the second step in the ubiquitination reaction that targets a protein for degradation via the proteasome. The ubiquitination process covalently attaches ubiquitin, a short protein of 76 amino acids, to a lysine residue on the target protein. Once a protein has been tagged with one ubiquitin molecule, additional rounds of ubiquitination form a polyubiquitin chain that is recognized by the proteasome's 19S regulatory particle, triggering the ATP-dependent unfolding of the target protein that allows passage into the proteasome's 20S core particle, where proteases degrade the target into short peptide fragments for recycling by the cell. Relationships A ubiquitin-activating enzyme, or E1, first activates the ubiquitin by covalently attaching the molecule to its active site cysteine residue. The activated ubiquitin is then transferred to an E2 cysteine. Once conjugated to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RIG-I
RIG-I (retinoic acid-inducible gene I) is a cytosolic pattern recognition receptor (PRR) responsible for the type-1 interferon (IFN1) response. RIG-I is an essential molecule in the innate immune system for recognizing cells that have been infected with a virus. These viruses can include West Nile virus, Japanese Encephalitis virus, influenza A, Sendai virus, flavivirus, and coronaviruses. RIG-I is structurally considered a helical ATP-dependent DExD/H box RNA helicase, that recognizes short viral double-stranded RNA (dsRNA) in the cytosol during a viral infection or other irregular RNAs (i.e., non-coding RNAs). Once activated by the dsRNA, the N-terminus caspase activation and recruitment domains (CARDs) migrate and bind with CARDs attached to mitochondrial antiviral signaling protein ( MAVS) to activate the signaling pathway for IFN1. IFN1s have three main functions: to limit the virus from spreading to nearby cells, promote an innate immune response, including inflammatory re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pattern Recognition Receptor
Pattern recognition receptors (PRRs) play a crucial role in the proper function of the innate immune system. PRRs are germline-encoded host sensors, which detect molecules typical for the pathogens. They are proteins expressed, mainly, by cells of the innate immune system, such as dendritic cells, macrophages, monocytes, neutrophils and epithelial cells, to identify two classes of molecules: pathogen-associated molecular patterns (PAMPs), which are associated with microbial pathogens, and damage-associated molecular patterns (DAMPs), which are associated with components of host's cells that are released during cell damage or death. They are also called primitive pattern recognition receptors because they evolved before other parts of the immune system, particularly before adaptive immunity. PRRs also mediate the initiation of antigen-specific adaptive immune response and release of inflammatory cytokines. The microbe-specific molecules that are recognized by a given PRR are called p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caspase Recruitment Domain
Caspase recruitment domains, or caspase activation and recruitment domains (CARDs), are interaction motifs found in a wide array of proteins, typically those involved in processes relating to inflammation and apoptosis. These domains mediate the formation of larger protein complexes via direct interactions between individual CARDs. CARD domains are found on a strikingly wide range of proteins, including helicases, kinases, mitochondrial proteins, caspases, and other cytoplasmic factors. Basic features CARD domains are a subclass of protein motif known as the death fold, which features an arrangement of six to seven antiparallel alpha helices with a hydrophobic core and an outer face composed of charged residues. Other motifs in this class include the pyrin domain (PYD), death domain (DD), and death effector domain (DED), all of which also function primarily in regulation of apoptosis and inflammatory responses. In apoptosis CARD domains were originally characterized based on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IRF3
Interferon regulatory factor 3, also known as IRF3, is an interferon regulatory factor. Function IRF3 is a member of the interferon regulatory transcription factor (IRF) family. IRF3 was originally discovered as a homolog of IRF1 and IRF2. IRF3 has been further characterized and shown to contain several functional domains including a nuclear export signal, a DNA-binding domain, a C-terminal IRF association domain and several regulatory phosphorylation sites. IRF3 is found in an inactive cytoplasmic form that upon serine/threonine phosphorylation forms a complex with CREBBP. The complex translocates into the nucleus for the transcriptional activation of interferons alpha and beta, and further interferon-induced genes. IRF3 plays an important role in the innate immune system's response to viral infection. Aggregated MAVS have been found to activate IRF3 dimerization. A 2015 study shows phosphorylation of innate immune adaptor proteins MAVS, STING and TRIF at a conserved pLxIS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NS1 Influenza Protein
The NS1 influenza protein (NS1) is a viral nonstructural protein encoded by the NS gene segments of type Influenza A virus, A, Influenza B, B and Influenza C virus, C influenza viruses. Also encoded by this segment is the nuclear export protein (NEP), formally referred to as NS2 (HCV), NS2 protein, which mediates the export of influenza virus ribonucleoprotein (RNP) complexes from the nucleus, where they are assembled.Influenza B and C Virus NEP (NS2) Proteins Possess Nuclear Export Activities Journal of Virology, August 2001, p. 7375-7383, Vol. 75, No. 16 Characteristics The NS1 of influenza A virus is a 26,000 Dalton protein. It prevents polyadenylation of cellular mRNAs to circumvent antiviral responses of the host, e ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
