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Ubiquilin-1
Ubiquilin-1 is a protein that in humans is encoded by the ''UBQLN1'' gene. Ubiquilins contain two domains, an N-terminal ubiquitin-like domain and a C-terminal ubiquitin-associated domain. They physically associate with both proteasomes and ubiquitin ligases, and thus are thought to functionally link the ubiquitination machinery to the proteasome to effect ''in vivo'' protein degradation. Functions Ubiquilin-1 is associated with protein degradation and aggregation of misfolded proteins, and may be involved in neurodegenerative diseases. Ubiquilin-1 has been reported to act as a molecular chaperone for amyloid precursor protein (APP), a protein associated with Alzheimer's disease. * Ubiquilin-1 was first identified through its interactions with presenilins. Two transcript variants encoding different isoforms have been found for this gene. Related proteins Human UBQLN1 shares a high degree of similarity with related ubiquilins including UBQLN2 and UBQLN4. Interaction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ubiquitin-associated Domain
Ubiquitin-associated (UBA) domains are protein domains that non-covalently interact with ubiquitin through protein-protein interactions. Ubiquitin is a small protein that is covalently linked to other proteins as part of intracellular signaling pathways, often as a signal for protein degradation. UBA domains are among the most common ubiquitin-binding domains. Function Proteins containing UBA domains are involved in a variety of additional cell processes, such as nucleotide excision repair (NER), spindle pole body duplication, and cell growth. Protein degradation via the ubiquitin proteasome system (UPS) allows the cell to selectively negatively regulate intracellular proteins. Protein degradation helps to maintain protein quality control, signalling, and cell cycle progression. UBA has been proposed to limit ubiquitin chain elongation and to target polyubiquitinated proteins to the 26S proteasome for degradation. They have been identified in modular proteins involved in ... [...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] |
Alzheimer's Disease
Alzheimer's disease (AD) is a neurodegeneration, neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in short-term memory, remembering recent events. As the disease advances, symptoms can include primary progressive aphasia, problems with language, Orientation (mental), disorientation (including easily getting lost), mood swings, loss of motivation, self-neglect, and challenging behaviour, behavioral issues. As a person's condition declines, they often withdraw from family and society. Gradually, bodily functions are lost, ultimately leading to death. Although the speed of progression can vary, the typical life expectancy following diagnosis is three to nine years. The cause of Alzheimer's disease is poorly understood. There are many environmental and genetic risk factors associated with its development. The strongest genetic risk factor is from an alle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PSEN2
Presenilin-2 is a protein that (in humans) is encoded by the ''PSEN2'' gene. Function Alzheimer's disease (AD) patients with an inherited form of the disease carry mutations in the presenilin proteins ( PSEN1; PSEN2) or the amyloid precursor protein (APP). These disease-linked mutations result in increased production of the longer form of amyloid-beta (main component of amyloid deposits found in AD brains). Presenilins are postulated to regulate APP processing through their effects on gamma-secretase, an enzyme that cleaves APP. Also, it is thought that the presenilins are involved in the cleavage of the Notch receptor, such that they either directly regulate gamma-secretase activity or themselves are protease enzymes. Two alternative transcripts of PSEN2 have been identified. In melanocytic cells PSEN2 gene expression may be regulated by MITF. Interactions PSEN2 has been shown to interact with: * BCL2-like 1, * CAPN1, * CIB1, * Calsenilin, * FHL2, * FLNB, * KCN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PSEN1
Presenilin-1 (PS-1) is a presenilin protein that in humans is encoded by the ''PSEN1'' gene. Presenilin-1 is one of the four core proteins in the gamma secretase complex, which is considered to play an important role in generation of amyloid beta (Aβ) from amyloid-beta precursor protein (APP). Accumulation of amyloid beta is associated with the onset of Alzheimer's disease. Structure Presenilin possesses a 9 transmembrane domain topology, with an extracellular C-terminus and a cytosolic N-terminus. Presenilin undergoes endo-proteolytic processing to produce ~27-28 kDa N-terminal and ~16-17 kDa C-terminal fragments in humans. Furthermore, presenilin exists in the cell mainly as a heterodimer of the C-terminal and N-terminus fragments. When presenilin 1 is overexpressed, the full length protein accumulates in an inactive form. Based on evidence that a gamma-secretase inhibitor binds to the fragments, the cleaved presenilin complex is considered to be the active form. Function ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P4HB
Protein disulfide-isomerase, also known as the beta- subunit of prolyl 4-hydroxylase (P4HB), is an enzyme that in humans encoded by the ''P4HB'' gene. The human ''P4HB'' gene is localized in chromosome 17q25. Unlike other prolyl 4-hydroxylase family proteins, this protein is multifunctional and acts as an oxidoreductase for disulfide formation, breakage, and isomerization. The activity of P4HB is tightly regulated. Both dimer dissociation and substrate binding are likely to enhance its enzymatic activity during the catalysis process. Structure P4HB has four thioredoxin domains (a, b, b’, and a’), with two CGHC active sites in the a and a’ domains. In both the reduced and oxidized state, these domains are arranged as a horseshoe shape. In reduced P4HB, domains a, b, and b' are in the same plane, while domain a' twists out at a ∼45° angle. When oxidized, the four domains stay in the same plane, and the distance between the active sites is larger than that in the reduced st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammalian Target Of Rapamycin
The mammalian target of rapamycin (mTOR), also referred to as the mechanistic target of rapamycin, and sometimes called FK506-binding protein 12-rapamycin-associated protein 1 (FRAP1), is a kinase that in humans is encoded by the ''MTOR'' gene. mTOR is a member of the phosphatidylinositol 3-kinase-related kinase family of protein kinases. mTOR links with other proteins and serves as a core component of two distinct protein complexes, mTOR complex 1 and mTOR complex 2, which regulate different cellular processes. In particular, as a core component of both complexes, mTOR functions as a serine/threonine protein kinase that regulates cell growth, cell proliferation, cell motility, cell survival, protein synthesis, autophagy, and transcription. As a core component of mTORC2, mTOR also functions as a tyrosine protein kinase that promotes the activation of insulin receptors and insulin-like growth factor 1 receptors. mTORC2 has also been implicated in the control and maintenance of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HERPUD1
Homocysteine-responsive endoplasmic reticulum-resident ubiquitin-like domain member 1 protein is a protein that in humans is encoded by the ''HERPUD1'' gene. The accumulation of unfolded proteins in the endoplasmic reticulum (ER) triggers the ER stress response. This response includes the inhibition of translation to prevent further accumulation of unfolded proteins, the increased expression of proteins involved in polypeptide folding, known as the unfolded protein response (UPR), and the destruction of misfolded proteins by the ER-associated protein degradation (ERAD) system. This gene may play a role in both UPR and ERAD. Its expression is induced by UPR and it has an ER stress response element in its promoter region while the encoded protein has an N-terminal ubiquitin-like domain which may interact with the ERAD system. This protein has been shown to interact with presenilin proteins and to increase the level of amyloid-beta protein following its overexpression. Alternative sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UBQLN4
Ubiquilin 4 is a protein in humans that is encoded by the UBQLN4 gene. Ubiquilin 4 regulates proteasomal protein degradation. Similarity to Other Proteins Human UBQLN4 shares a high degree of similarity with related ubiquilins including UBQLN1 and UBQLN2 Ubiquilin-2 is a protein that in humans is encoded by the ''UBQLN2'' gene. Function This gene encodes a ubiquitin-like protein ( ubiquilin) that shares high degree of similarity with related products in yeast, rat and frog. Ubiquilins contain .... References External links * {{gene-1-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UBQLN2
Ubiquilin-2 is a protein that in humans is encoded by the ''UBQLN2'' gene. Function This gene encodes a ubiquitin-like protein ( ubiquilin) that shares high degree of similarity with related products in yeast, rat and frog. Ubiquilins contain a N-terminal ubiquitin-like domain and a C-terminal ubiquitin-associated domain. They physically associate with both proteasomes and ubiquitin ligases, and are thus thought to functionally link the ubiquitination machinery to the proteasome to effect ''in vivo'' protein degradation. This ubiquilin has also been shown to bind the ATPase domain of the Hsp70-like Stch protein. Similarity to other proteins Human UBQLN2 shares a high degree of similarity with related ubiquilins including UBQLN1 and UBQLN4. Clinical significance In a small proportion of familial amyotrophic lateral sclerosis (fALS), the UBQLN2 gene is mutated, causing formation of a non-functional Ubiquilin 2 enzyme. This non-functioning enzyme leads to the accumulatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
