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Skp1
S-phase kinase-associated protein 1 is an enzyme that in humans is encoded by the ''SKP1'' gene. This gene encodes a protein that is a member of the SCF ubiquitin ligase protein complex. It binds to F-box proteins (proteins containing an F-box motif), such as cyclin F, S-phase kinase-associated protein 2, and other regulatory proteins involved in ubiquitin dependent proteolysis. The encoded protein also collaborates with a network of proteins to control beta-catenin levels and affects the activity level of beta-catenin dependent TCF transcription factors. Studies have also characterized the protein as an RNA polymerase II elongation factor. Alternative splicing of this gene results in two transcript variants. A related pseudogene has been identified on chromosome 7. Interactions SKP1A has been shown to interact with: * BTRC, * CACYBP, * CDCA3, * CDK9, * CUL1, * FBXL3, * FBXO4, * FBXO5, * FBXO7, * FBXW2, * FBXW7, and * SKP2 S-phase kinase-associated protein 2 i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCF Complex
Skp, Cullin, F-box containing complex (or SCF complex) is a multi-protein E3 ubiquitin ligase complex that catalyzes the ubiquitination of proteins destined for 26S proteasomal degradation. Along with the anaphase-promoting complex, SCF has important roles in the ubiquitination of proteins involved in the cell cycle. The SCF complex also marks various other cellular proteins for destruction. Core components SCF contains a variable F-box protein and three core subunits: *F-box protein (FBP) – FBP contributes to the substrate specificity of the SCF complex by first aggregating to target proteins independently of the complex. Each FBP (e.g. Skp2) may recognize several different substrates in a manner that is dependent on post-translational modifications such as phosphorylation or glycosylation. FBP then binds to Skp1 of the SCF complex using an F-box motif, bringing the target protein into proximity with the functional E2 ubiquitin-conjugating enzyme. FBP is also essential in reg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SKP2
S-phase kinase-associated protein 2 is an enzyme that in humans is encoded by the ''SKP2'' gene. Structure and function Skp2 contains 424 residues in total with the ~40 amino acid F-box domain lying closer to the N-terminal region at the 94-140 position and the C-terminal region forming a concave surface consisting of ten leucine-rich repeats (LRRs). The F-box proteins constitute one of the four subunits of ubiquitin protein ligase complex called SCFs (SKP1-cullin-F-box), which often—but not always—recognize substrates in a phosphorylation-dependent manner. In this SCF complex, Skp2 acts as the substrate recognition factor. F-box Domain The F-box proteins are divided into three classes: Fbxws containing WD40 repeat domains, Fbxls containing leucine-rich repeats, and Fbxos containing either different protein–protein interaction modules or no recognizable motifs. The protein encoded by this gene belongs to the Fbxls class. In addition to an F-box, this protein contains 10 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
F-box Proteins
F-box proteins are proteins containing at least one F-box domain. The first identified F-box protein is one of three components of the SCF complex, which mediates ubiquitination of proteins targeted for degradation by the 26S proteasome. Core components F-box domain is a protein structural motif of about 50 amino acids that mediates protein–protein interactions. It has consensus sequence and varies in few positions. It was first identified in cyclin F. The F-box motif of Skp2, consisting of three alpha-helices, interacts directly with the SCF protein Skp1. F-box domains commonly exist in proteins in cancer with other protein–protein interaction motifs such as leucine-rich repeats (illustrated in the Figure) and WD repeats, which are thought to mediate interactions with SCF substrates. Function F-box proteins have also been associated with cellular functions such as signal transduction and regulation of the cell cycle. In plants, many F-box proteins are represented in gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ubiquitin Ligase
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 reg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BTRC (gene)
F-box/WD repeat-containing protein 1A (FBXW1A) also known as βTrCP1 or Fbxw1 or hsSlimb or pIkappaBalpha-E3 receptor subunit is a protein that in humans is encoded by the ''BTRC'' (beta-transducin repeat containing) gene. This gene encodes a member of the F-box protein family which is characterized by an approximately 40 residue structural motif, the F-box. The F-box proteins constitute one of the four subunits of ubiquitin protein ligase complex called SCFs ( Skp1-Cul1-F-box protein), which often, but not always, recognize substrates in a phosphorylation-dependent manner. F-box proteins are divided into 3 classes: * Fbxws containing WD40 repeats, * Fbxls containing leucine-rich repeats, * and Fbxos containing either "other" protein–protein interaction modules or no recognizable motifs. The protein encoded by this gene belongs to the Fbxw class as, in addition to an F-box, this protein contains multiple WD40 repeats. This protein is homologous to Xenopus βTrCP, yeast Met30, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ubiquitin
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, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CDK9
Cyclin-dependent kinase 9 or CDK9 is a cyclin-dependent kinase associated with P-TEFb. Function The protein encoded by this gene is a member of the cyclin-dependent kinase (CDK) family. CDK family members are highly similar to the gene products of S. cerevisiae cdc28, and S. pombe cdc2, and known as important cell cycle regulators. This kinase was found to be a component of the multiprotein complex TAK/P-TEFb, which is an elongation factor for RNA polymerase II-directed transcription and functions by phosphorylating the C-terminal domain of the largest subunit of RNA polymerase II. This protein forms a complex with and is regulated by its regulatory subunit cyclin T or cyclin K. HIV-1 Tat protein was found to interact with this protein and cyclin T, which suggested a possible involvement of this protein in AIDS. CDK9 is also known to associate with other proteins such as TRAF2, and be involved in differentiation of skeletal muscle. Inhibitors Based on molecular docking resul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FBXW2
F-box/WD repeat-containing protein 2 is a protein that in humans is encoded by the ''FBXW2'' gene. Function F-box proteins are an expanding family of eukaryotic proteins characterized by an approximately 40 amino acid motif, the F box. Some F-box proteins have been shown to be critical for the ubiquitin-mediated degradation of cellular regulatory proteins. In fact, F-box proteins are one of the four subunits of ubiquitin protein ligases, called SCFs. SCF ligases bring ubiquitin conjugating enzymes to substrates that are specifically recruited by the different F-box proteins. Mammalian F-box proteins are classified into three groups based on the presence of either WD-40 repeats, leucine-rich repeats, or the presence or absence of other protein-protein interacting domains. This gene encodes the second identified member of the F-box gene family and contains multiple WD-40 repeats. Interactions FBXW2 has been shown to interact with SKP1A S-phase kinase-associated protein 1 is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FBXO7
F-box only protein 7 is a protein that in humans is encoded by the ''FBXO7'' gene. Mutations in FBXO7 have been associated with Parkinson's disease. Function This gene encodes a member of the F-box protein family which is characterized by an approximately 40 amino acid motif, the F-box. The F-box proteins constitute one of the four subunits of the ubiquitin protein ligase complex called SCFs (SKP1-cullin-F-box), which function in phosphorylation-dependent ubiquitination. The F-box proteins are divided into 3 classes: Fbws containing WD-40 domains, Fbls containing leucine-rich repeats, and Fbxs containing either different protein-protein interaction modules or no recognizable motifs. The protein encoded by this gene belongs to the Fbxs class and it may play a role in regulation of hematopoiesis. Alternatively spliced transcript variants of this gene have been identified with the full-length natures of only some variants being determined. Interactions FBXO7 has been shown to in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FBXO5
F-box only protein 5 is a protein that in humans is encoded by the ''FBXO5'' gene. Function This gene encodes a member of the F-box protein family which is characterized by an approximately 40 amino acid motif, the F-box. The F-box proteins constitute one of the four subunits of the ubiquitin protein ligase complex called SCFs (SKP1-cullin-F-box), which function in phosphorylation-dependent ubiquitination. The F-box proteins are divided into 3 classes: Fbws containing WD-40 domains, Fbls containing leucine-rich repeats, and Fbxs containing either different protein-protein interaction modules or no recognizable motifs. The protein encoded by this gene belongs to the Fbxs class. This protein is similar to xenopus early mitotic inhibitor-1 (Emi1), which is a mitotic regulator that interacts with Cdc20 and inhibits the anaphase promoting complex. Moreover, Emi1 also assembles a CRL1 complex that targets RAD51 for ubiquitin-mediated degradation. Disease Gene and protein expressi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FBXO4
F-box only protein 4 is a protein that in humans is encoded by the ''FBXO4'' gene. Function This gene encodes a member of the F-box protein family which is characterized by an approximately 40 amino acid motif, the F-box. The F-box proteins constitute one of the four subunits of the ubiquitin ligase complex called SCFs (SKP1-cullin-F-box), which function in phosphorylation-dependent ubiquitination. The F-box proteins are divided into 3 classes: Fbws containing WD-40 domains, Fbls containing leucine-rich repeats, and Fbxs containing either different protein-protein interaction modules or no recognizable motifs. The protein encoded by this gene belongs to the Fbxs class. Alternative splicing of this gene generates 2 transcript variants. Interactions FBXO4 has been shown to interact with: * CUL1, and * SKP1A S-phase kinase-associated protein 1 is an enzyme that in humans is encoded by the ''SKP1'' gene. This gene encodes a protein that is a member of the SCF ubiquitin lig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
