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HSP90
Hsp90 (heat shock protein 90) is a chaperone protein that assists other proteins to fold properly, stabilizes proteins against heat stress, and aids in protein degradation. It also stabilizes a number of proteins required for tumor growth, which is why Hsp90 inhibitors are investigated as anti-cancer drugs. Heat shock proteins, as a class, are among the most highly expressed cellular proteins across all species. As their name implies, heat shock proteins protect cells when stressed by elevated temperatures. They account for 1–2% of total protein in unstressed cells. However, when cells are heated, the fraction of heat shock proteins increases to 4–6% of cellular proteins. Heat shock protein 90 (Hsp90) is one of the most common of the heat-related proteins. The "90" comes from the fact that it has a mass of roughly 90 kilodaltons. A 90 kDa protein is considered fairly large for a non-fibrous protein. Hsp90 is found in bacteria and all branches of eukarya ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HSP90AA1
Heat shock protein HSP 90-alpha is a protein that in humans is encoded by the ''HSP90AA1'' gene. Function The gene, HSP90AA1, encodes the human stress-inducible 90-kDa heat shock protein alpha (Hsp90A). Complemented by the constitutively expressed paralog Hsp90B which shares over 85% amino acid sequence identity, Hsp90A expression is initiated when a cell experiences proteotoxic stress. Once expressed Hsp90A dimers operate as molecular chaperones that bind and fold other proteins into their functional 3-dimensional structures. This molecular chaperoning ability of Hsp90A is driven by a cycle of structural rearrangements fueled by ATP hydrolysis. Current research on Hsp90A focuses in its role as a drug target due to its interaction with a large number of tumor promoting proteins and its role in cellular stress adaptation. Gene structure Human HSP90AA1 is encoded on the complement strand of Chromosome 14q32.33 and spans over 59 kbp. Several pseudogenes of HSP90AA1 exist th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hsp90 Inhibitor
An Hsp90 inhibitor is a substance that inhibits that activity of the Hsp90 heat shock protein. Since Hsp90 stabilizes a variety of proteins required for survival of cancer cells, these substances may have therapeutic benefit in the treatment of various types of malignancies. Furthermore, a number of Hsp90 inhibitors are currently undergoing clinical trials for a variety of cancers. Hsp90 inhibitors include the natural products geldanamycin and radicicol as well as semisynthetic derivatives 17-N-Allylamino-17-demethoxygeldanamycin (17AAG). Mechanism of action Among heat shock proteins the focus on HSP90 has increased due to its involvement in several cellular phenomena and more importantly in disease progression. HSP90 keeps the death proteins in an apoptosis resistant state by direct association. Its wide range of functions results from the ability of HSP90 to chaperone several client proteins that play a central pathogenic role in human diseases including cancer, neurodegen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HSP90AB1
Heat shock protein HSP 90-beta also called HSP90beta is a protein that in humans is encoded by the ''HSP90AB1'' gene. Function HSP90AB1 is a molecular chaperone. Chaperones are proteins that bind to other proteins, thereby stabilizing them in an ATP-dependent manner. Chaperones stabilize new proteins during translation, mature proteins which are partially unstable but also proteins that have become partially denatured due to various kinds of cellular stress. In case proper folding or refolding is impossible, HSPs mediate protein degradation. They also have specialized functions, such as intracellular transport into organelles. Classification Human HSPs are classified into 5 major groups according to the HGNC: * HSP70 * DnaJ (HSP40) * HSPB (small heat shock proteins) * HSPC (HSP90) * chaperonins Chaperonins are characterized by their barrel-shaped structure with binding sites for client proteins inside the barrels. The human HSP90 group consists of 5 members according to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Shock Protein
Heat shock proteins (HSP) are a family of proteins produced by cells in response to exposure to stressful conditions. They were first described in relation to heat shock, but are now known to also be expressed during other stresses including exposure to cold, UV light and during wound healing or tissue remodeling. Many members of this group perform chaperone functions by stabilizing new proteins to ensure correct folding or by helping to refold proteins that were damaged by the cell stress. This increase in expression is transcriptionally regulated. The dramatic upregulation of the heat shock proteins is a key part of the heat shock response and is induced primarily by heat shock factor (HSF). HSPs are found in virtually all living organisms, from bacteria to humans. Heat-shock proteins are named according to their molecular weight. For example, HSP60, Hsp60, Hsp70 and Hsp90 (the most widely studied HSPs) refer to families of heat shock proteins on the order of 60, 70 and 90 ato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaperone (protein)
In molecular biology, molecular chaperones are proteins that assist the conformational folding or unfolding of large proteins or macromolecular protein complexes. There are a number of classes of molecular chaperones, all of which function to assist large proteins in proper protein folding during or after synthesis, and after partial denaturation. Chaperones are also involved in the translocation of proteins for proteolysis. The first molecular chaperones discovered were a type of assembly chaperones which assist in the assembly of nucleosomes from folded histones and DNA. One major function of molecular chaperones is to prevent the aggregation of misfolded proteins, thus many chaperone proteins are classified as heat shock proteins, as the tendency for protein aggregation is increased by heat stress. The majority of molecular chaperones do not convey any steric information for protein folding, and instead assist in protein folding by binding to and stabilizing folding interme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HSP90AA2
Heat shock protein 90kDa alpha (cytosolic), class A member 2, also known as HSP90AA2, is a human gene. The protein encoded by this gene belongs to the Hsp90 family of heat shock protein Heat shock proteins (HSP) are a family of proteins produced by cells in response to exposure to stressful conditions. They were first described in relation to heat shock, but are now known to also be expressed during other stresses including expo ...s. References {{gene-11-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryote
Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacteria and Archaea (both prokaryotes) make up the other two domains. The eukaryotes are usually now regarded as having emerged in the Archaea or as a sister of the Asgard archaea. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among archaea. Eukaryotes represent a small minority of the number of organisms, but, due to their generally much larger size, their collective global biomass is estimated to be about equal to that of prokaryotes. Eukaryotes emerged approximately 2.3–1.8 billion years ago, during the Proterozoic eon, likely as flagellated phagotrophs. Their name comes from the Greek εὖ (''eu'', "well" or "good") and κάρυον (''karyon'', "nut" or "kernel"). Euka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denaturation (biochemistry)
In biochemistry, denaturation is a process in which proteins or nucleic acids lose the quaternary structure, tertiary structure, and secondary structure which is present in their native state, by application of some external stress or compound such as a strong acid or base, a concentrated inorganic salt, an organic solvent (e.g., alcohol or chloroform), agitation and radiation or heat. If proteins in a living cell are denatured, this results in disruption of cell activity and possibly cell death. Protein denaturation is also a consequence of cell death. Denatured proteins can exhibit a wide range of characteristics, from conformational change and loss of solubility to aggregation due to the exposure of hydrophobic groups. The loss of solubility as a result of denaturation is called ''coagulation''. Denatured proteins lose their 3D structure and therefore cannot function. Protein folding is key to whether a globular or membrane protein can do its job correctly; it must be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yeast
Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constitute 1% of all described fungal species. Yeasts are unicellular organisms that evolved from multicellular ancestors, with some species having the ability to develop multicellular characteristics by forming strings of connected budding cells known as pseudohyphae or false hyphae. Yeast sizes vary greatly, depending on species and environment, typically measuring 3–4 µm in diameter, although some yeasts can grow to 40 µm in size. Most yeasts reproduce asexually by mitosis, and many do so by the asymmetric division process known as budding. With their single-celled growth habit, yeasts can be contrasted with molds, which grow hyphae. Fungal species that can take both forms (depending on temperature or other conditions) are ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytosol
The cytosol, also known as cytoplasmic matrix or groundplasm, is one of the liquids found inside cells (intracellular fluid (ICF)). It is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondrion into many compartments. In the eukaryotic cell, the cytosol is surrounded by the cell membrane and is part of the cytoplasm, which also comprises the mitochondria, plastids, and other organelles (but not their internal fluids and structures); the cell nucleus is separate. The cytosol is thus a liquid matrix around the organelles. In prokaryotes, most of the chemical reactions of metabolism take place in the cytosol, while a few take place in membranes or in the periplasmic space. In eukaryotes, while many metabolic pathways still occur in the cytosol, others take place within organelles. The cytosol is a complex mixture of substances dissolved in water. Although water forms the large majority of the cytosol, its structure and prope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant species of mammals have been described divided into 29 orders. The largest orders, in terms of number of species, are the rodents, bats, and Eulipotyphla (hedgehogs, moles, shrews, and others). The next three are the Primates (including humans, apes, monkeys, and others), the Artiodactyla ( cetaceans and even-toed ungulates), and the Carnivora (cats, dogs, seals, and others). In terms of cladistics, which reflects evolutionary history, mammals are the only living members of the Synapsida (synapsids); this clade, together with Saur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] |
