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Co-chaperone
Co-chaperones are proteins that assist chaperones in protein folding and other functions. Co-chaperones are the non-client binding molecules that assist in protein folding mediated by Hsp70 and Hsp90. They are particularly essential in stimulation of the ATPase activity of these chaperone proteins. There are a great number of different co-chaperones however based on their domain structure most of them fall into two groups: J-domain proteins and tetratricopeptide repeats (TPR). Co-chaperones assist heat shock proteins in the protein folding process. These co-chaperones can function in a number of ways. Primarily co-chaperones are involved in the ATPase functionality of their associated heat shock proteins. Co-chaperones catalyze the hydrolysis ATP to ADP on their respective chaperones which then allows them undergo a large conformational change that allows them to either bind to their substrates with higher affinity or aid in the release of the substrate following protein folding, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hop (protein)
Hop, occasionally written HOP, is an abbreviation for Hsp70-Hsp90 Organizing Protein. It functions as a co-chaperone which reversibly links together the protein chaperones Hsp70 and Hsp90. Hop belongs to the large group of co-chaperones, which regulate and assist the major chaperones (mainly heat shock proteins). It is one of the best studied co-chaperones of the Hsp70/Hsp90-complex. It was first discovered in yeast and homologues were identified in human, mouse, rat, insects, plants, parasites, and virus. The family of these proteins is referred to as STI1 (stress inducible protein) and can be divided into yeast, plant, and animal STI1 (Hop). Synonyms Gene The gene for human Hop is located on chromosome 11q13.1 and consists of 14 exons. Structure STI proteins are characterized by some structural features: All homologues have nine tetratricopeptide repeat (TPR) motifs, that are clustered into domains of three TPRs. The TPR motif is a very common structural feature use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CDC37
Hsp90 co-chaperone Cdc37 is a protein that in humans is encoded by the ''CDC37'' gene. The protein encoded by this gene is highly similar to Cdc 37, a cell division cycle control protein of Saccharomyces cerevisiae. This protein is a HSP90 Co-chaperone with specific function in cell signal transduction. It has been shown to form complex with Hsp90 and a variety of protein kinases including CDK4, CDK6, SRC, RAF1, MOK, as well as eIF-2 alpha kinases. It is thought to play a critical role in directing Hsp90 to its target kinases. Interactions CDC37 has been shown to interact with: * CDK4, * HSP90AA1 * IKBKG, * IKK2, and * STK11. Domain architecture CDC37 consists of three structural domains. The N-terminal domain binds to protein kinases. The central domain is the 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 sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GrpE
GrpE (''Gro-P'' like protein E) is a bacterial nucleotide exchange factor that is important for regulation of protein folding machinery, as well as the heat shock response. It is a heat-inducible protein and during stress it prevents unfolded proteins from accumulating in the cytoplasm. Accumulation of unfolded proteins in the cytoplasm can lead to cell death. Discovery GrpE is a nucleotide exchange factor that was first discovered by researchers in 1977 as a protein necessary to propagate bacteriophage λ, a virus that infects bacteria by highjacking the bacteria's own replication machinery, in ''Escherichia coli''. By using a genetic screen, researchers knocked out certain genes in E''. coli'' and then tested whether the bacteria was able to replicate, GrpE was found to be crucial to propagation. Since that time, GrpE has been identified in all bacteria and in Archaea where DnaK and DnaJ are present. The crystal structure of GrpE was determined in 1997 at 2.8 Angstrom and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DnaJ
In molecular biology, chaperone DnaJ, also known as Hsp40 (heat shock protein 40 kD), is a molecular chaperone protein. It is expressed in a wide variety of organisms from bacteria to humans. Function Molecular chaperones are a diverse family of proteins that function to protect proteins from irreversible aggregation during synthesis and in times of cellular stress. The bacterial molecular chaperone DnaK is an enzyme that couples cycles of ATP binding, hydrolysis, and ADP release by an N-terminal ATP-hydrolyzing domain to cycles of sequestration and release of unfolded proteins by a C-terminal substrate binding domain. Dimeric GrpE is the co-chaperone for DnaK, and acts as a nucleotide exchange factor, stimulating the rate of ADP release 5000-fold. DnaK is itself a weak ATPase; ATP hydrolysis by DnaK is stimulated by its interaction with another co-chaperone, DnaJ. Thus the co-chaperones DnaJ and GrpE are capable of tightly regulating the nucleotide-bound and substrate-bound s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaperone DnaJ
In molecular biology, chaperone DnaJ, also known as Hsp40 (heat shock protein 40 kD), is a molecular chaperone protein. It is expressed in a wide variety of organisms from bacteria to humans. Function Molecular chaperones are a diverse family of proteins that function to protect proteins from irreversible aggregation during synthesis and in times of cellular stress. The bacterial molecular chaperone DnaK is an enzyme that couples cycles of ATP binding, hydrolysis, and ADP release by an N-terminal ATP-hydrolyzing domain to cycles of sequestration and release of unfolded proteins by a C-terminal substrate binding domain. Dimeric GrpE is the co-chaperone for DnaK, and acts as a nucleotide exchange factor, stimulating the rate of ADP release 5000-fold. DnaK is itself a weak ATPase; ATP hydrolysis by DnaK is stimulated by its interaction with another co-chaperone, DnaJ. Thus the co-chaperones DnaJ and GrpE are capable of tightly regulating the nucleotide-bound and substrate-bound sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacsin
Sacsin also known as DnaJ homolog subfamily C member 29 (DNAJC29) is a protein that in humans is encoded by the ''SACS'' gene. Sacsin is a Hsp70 co-chaperone. Function This gene consists of nine exons including a gigantic exon spanning more than 12.8k bp. It encodes the sacsin protein, which includes a UBQ region at the N-terminus, a HEPN domain at the C-terminus and a Chaperone DnaJ, DnaJ region upstream of the HEPN domain. This modular protein is essential for normal mitochondrial network organization. The gene is highly expressed in the central nervous system, also found in skin, skeletal muscles and at low levels in the pancreas. Mutations in this gene result in autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS), a neurodegenerative disorder characterized by early-onset cerebellar ataxia with spasticity and peripheral neuropathy. Clinical significance Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a very rare neurodegenerative genet ... [...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 inter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hsp70
The 70 kilodalton heat shock proteins (Hsp70s or DnaK) are a family of conserved ubiquitously expressed heat shock proteins. Proteins with similar structure exist in virtually all living organisms. Intracellularly localized Hsp70s are an important part of the cell's machinery for protein folding, performing chaperoning functions, and helping to protect cells from the adverse effects of physiological stresses. Additionally, membrane-bound Hsp70s have been identified as a potential target for cancer therapies and their extracellularly localized counterparts have been identified as having both membrane-bound and membrane-free structures. Discovery Members of the Hsp70 family are very strongly upregulated by heat stress and toxic chemicals, particularly heavy metals such as arsenic, cadmium, copper, mercury, etc. Heat shock was originally discovered by Ferruccio Ritossa in the 1960s when a lab worker accidentally boosted the incubation temperature of Drosophila (fruit flies). When ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNAJB6
DnaJ homolog subfamily B member 6 is a protein that in humans is encoded by the ''DNAJB6'' gene. Function This gene encodes a member of the DNAJ protein family. DNAJ family members are characterized by a highly conserved amino acid stretch called the 'J-domain' and function as one of the two major classes of molecular chaperones involved in a wide range of cellular events, such as protein folding and oligomeric protein complex assembly. This family member may also play a role in polyglutamine aggregation in specific neurons. Alternative splicing of this gene results in multiple transcript variants; however, not all variants have been fully described. Interactions DNAJB6 has been shown to interact with keratin 18 Keratin 18 is a type I cytokeratin. It is, together with its filament partner keratin 8, perhaps the most commonly found products of the intermediate filament gene family. They are expressed in single layer epithelial tissues of the body. Mutations .... It has been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AHSA2
AHSA2 also known as AHA1, activator of heat shock 90kDa protein ATPase homolog 2 (yeast) is a human gene which encodes a protein which acts as co-chaperone of Hsp90 (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 exp ... 90). AHSA2 and the related AHSA1 belongs to the AHA (Activator of Hsp90 ATPase) family of stress-regulated proteins that bind directly to Hsp90 and are required for Hsp90-dependent activation of client proteins. References {{protein-stub Co-chaperones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SGTA
Small glutamine-rich tetratricopeptide repeat-containing protein alpha is a protein that in humans is encoded by the ''SGTA'' gene. ''SGTA'' orthologs have also been identified in several mammals for which complete genome data are available. Function This gene encodes a protein which is capable of interacting with the major nonstructural protein of parvovirus H-1 and 70-kDa heat shock cognate protein; however, its function is not known. Since this transcript is expressed ubiquitously in various tissues, this protein may serve a housekeeping function. Interactions SGTA has been shown to interact with Growth hormone receptor Growth hormone receptor is a protein that in humans is encoded by the ''GHR'' gene. GHR orthologs have been identified in most mammals. Structure Growth hormone receptor (GHR) is a transmembrane protein consisting of 620 amino acids. The rece .... References Further reading * * * * * * * * * * * * * * * * Co-chaperones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
