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GroEL protein is the major heat shock protein of E.coli and belongs to the chaperonin (HSP60) family. GroEL protein prevents misfolding of proteins and promotes the refolding and proper assembly of unfolded polypeptiedes generated under stress condition.

HSP90 has been identified in the cytosol, nucleus and endoplasmic reticulum, and is reported to exist in many tissue types. In several tissues, including smooth muscle, HSP90 comprises up to 2% of total cellular protein. HSP90 functions as a dimer, assembled as part of heterocomplex. It possesses ATP-binding site and low ATPase activity. HSP90 is able to associate with actin filaments in certain conditions. Another important property of HSP90 is the binding of unoccupied steroid hormone receptors. HSP90 has been characterized as a molecular chaperone able to keep the target protein in a folding-competent state. It has an enhanced chaperone activity in oligomeric form at high temperatures. HSP90 function is sensitive to bivalent cations concentration.

GroEL, HSP60 is a chaperonin located in the mitochondria which is responsible for the transportation & refolding of proteins from the cytoplasm directly into the mitochondrial matrix. GroEL is regulated by the HSP10 cochaperonin, which is a single heptameric protein ring having a molecular mass of 10 kDa which form a unique complex with HSP60. HSP10, GroES coordinates the ATPase activity of the HSP60 subunits in order to allow the release of bound polypeptide in a manner that is productive for its correct folding.

SERPINH1 is part of the serpin superfamily of serine proteinase inhibitors. SEPINH1 expression is induced by heat shock. HSP47 localizes to the endoplasmic reticulum lumen and binds collagen therefore it is a molecular chaperone which takes part in the maturation of collagen molecules, facilitating the folding and assembly of procollagen molecules, retaining unfolded molecules within the ER, and assisting the transport of correctly folded-molecules from the ER to Golgi apparatus. Autoantibodies to HSP47 protein have been found in rheumatoid arthritis. SERPINH1 binds specifically to collagen and acts as a chaperone in the biosynthetic pathway of collagen.

DnaJ homolog subfamily B member 6 (DNAJB6) belongs to the DNAJ protein family. The DNAJ family members are characterized by a highly conserved amino acid stretch known as 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. DNAJB6 may also play a role in polyglutamine aggregation in specific neurons.

HSP90B1 is an abundant molecular chaperone resident endoplasmic reticulum (ER) lumenal stress protein which is part of the Hsp90 family. HSP90B1 is involved in maintaining protein homeostasis in the secretory pathway as well as functioning in the intracellular trafficking of peptides from the extracellular space to the MHC class I antigen processing pathway of antigen presentation cells. HSP90B1 has key roles in signal transduction, protein folding, protein degradation, and morphologic evolution. HSP90B1 protein associates with numerous cochaperones and involved in folding of newly synthesized proteins or stabilizing and refolding denatured proteins after stress. HSP90B1 is highly expressed in human gastric carcinoma BGC-823 cells during the whole cell cycle.

HSP10 is part of the molecular chaperons, that are crucial for thir efficient folding of proteins in normal as well as stress conditions. GroES function is to bind to HSP60 in the presence of ATP, thus causing a change in the HSP60 conformation & enclosing the protein substrate within the complex. ATP hydrolysis by chaperonin-60 which destabilizes the HSP10-HSP60 complex, thereby allowing it to dissociate and secrete the substrate protein. GroES having the NCBI accession number of NP_002148 was purified by using conventional chromatography techniques.

GroEL, HSP60 is a chaperonin located in the mitochondria which is responsible for the transportation & refolding of proteins from the cytoplasm directly into the mitochondrial matrix. GroEL is regulated by the HSP10 cochaperonin, which is a single heptameric protein ring having a molecular mass of 10 kDa which form a unique complex with HSP60. HSP10, GroES coordinates the ATPase activity of the HSP60 subunits in order to allow the release of bound polypeptide in a manner that is productive for its correct folding.

DnaK, originally identified for its DNA replication by bacteriophage l in E. coli is the bacterial hsp70 chaperone. This protein is involved in the folding and assembly of newly synthesized polypeptide chains and in preventing the aggregation of stress-denatured proteins. Dnak(residues 508-638) of the substrate binding domain is a-helical and appears to act as a lid covering the substrate binding cleft. DnaK(amino acid 508-638) was purified to apparent homogeneity by using conventional column chromatography techniques. Additional amino acid (Met) is attached at N- terminus.

HSP90B1 is an abundant molecular chaperone resident endoplasmic reticulum (ER) lumenal stress protein which is part of the Hsp90 family. HSP90B1 is involved in maintaining protein homeostasis in the secretory pathway as well as functioning in the intracellular trafficking of peptides from the extracellular space to the MHC class I antigen processing pathway of antigen presentation cells. HSP90B1 has key roles in signal transduction, protein folding, protein degradation, and morphologic evolution. HSP90B1 protein associates with numerous cochaperones and involved in folding of newly synthesized proteins or stabilizing and refolding denatured proteins after stress. HSP90B1 is highly expressed in human gastric carcinoma BGC-823 cells during the whole cell cycle.

DnaJ (Hsp40) Homolog, Subfamily B, Member 4 (DNAJB4) is a member of the evolutionarily conserved DNAJ/HSP40 protein family. DNAJB4 subunit configuration is homodimer. DNAJB4 possibly functions as a chaperone. DNAJB4 C-terminal section interacts with the C-terminal tail of OPRM1. DNAJB4 also has an interaction with SDIM1. DNAJB4 is expressed in the heart, pancreas and skeletal muscle, and to a lesser extent in the brain, placenta and liver.

HSP90B1 is an abundant molecular chaperone resident endoplasmic reticulum (ER) lumenal stress protein which is part of the Hsp90 family. HSP90B1 is involved in maintaining protein homeostasis in the secretory pathway as well as functioning in the intracellular trafficking of peptides from the extracellular space to the MHC class I antigen processing pathway of antigen presentation cells. HSP90B1 has key roles in signal transduction, protein folding, protein degradation, and morphologic evolution. HSP90B1 protein associates with numerous cochaperones and involved in folding of newly synthesized proteins or stabilizing and refolding denatured proteins after stress. HSP90B1 is highly expressed in human gastric carcinoma BGC-823 cells during the whole cell cycle.

Human HSP40 (heat shock protein with molecular size of 40kDa) is one of the mammalian homologues of bacterial DnaJ heat shock protein and regulates cellular processes by aiding in the folding, transport and assembly. HSP40 protein contains the J-domain which controls interaction with the ATPase domain of DnaK.

Dsb proteins are in charge for the formation and rearrangement of disulfide bonds during the folding of secreted and membrane proteins in bacteria. DsbG has disulfide bond isomerase and chaperone activity. DsbG interacts with refolding intermediates of chemically denatured citrate synthase and prevents their aggregation in vitro. DsbG shares sequnce homology with DsbC. DsbG forms a stable periplasmic dimer and displays an equilibrium constant with glutathione comparable with DsbA and DsbC. DsbG is expressed at roughly 25% level of DsbC.

ST13 is an adaptor protein (co-chaperone) that mediates the association of HSP70 & HSP90 and appears in early receptor complexes. ST13 plays a role in the assembly process of glucocorticoid receptor, which requires the assistance of multiple molecular chaperones. The expression of ST13 is downregulated in colorectal carcinoma tissue signifying that is candidate tumor suppressor gene. Through common binding to both Hsp70 and Hsp90, ST13 functions as an adaptor that can integrate Hsp70 and Hsp90 interactions. The expression of ST13 decreases in colorectal cancer tissue compared with that in adjacent normal tissue. ST13 is mostly expressed in colorectal epithelia and adenocarcinoma cells. ST13 functions to promote the efficiency of glucocorticoid receptor maturation in cells. The expression levels of the ST13 gene were significantly decreased in primary tumors compared with adjacent mucosa.

AHA1 is a cochaperone that stimulates hsp90 ATPase activity. AHSA1 binds the middle domain of Hsp90 (amino acid 272-627) and functions as an ATPase-activating protein that competes with p23 and other co-chaperones for Hsp90 binding.
AHA1 affects a step in the endoplasmic reticulum to golgi trafficking.

GroEL, HSP60 is a chaperonin located in the mitochondria which is responsible for the transportation & refolding of proteins from the cytoplasm directly into the mitochondrial matrix. GroEL is regulated by the HSP10 cochaperonin, which is a single heptameric protein ring having a molecular mass of 10 kDa which form a unique complex with HSP60. HSP10, GroES coordinates the ATPase activity of the HSP60 subunits in order to allow the release of bound polypeptide in a manner that is productive for its correct folding.

DnaJ (Hsp40) Homolog, Subfamily C, Member 27 (DNAJC27) which contains one J domain is a part of the small GTPase superfamily. DNAJC27 is a GTPase which activates the MEK/ERK pathway and induces cell transformation when overexpressed.

DNAJC19 is part of a complex involved in the ATP-dependent transport of transit peptide-containing proteins from the inner cell membrane to the mitochondrial matrix. DNAJC19 is a single-pass membrane protein which contains a J domain and is localized to the inner membrane of the mitochondrion. Expressed ubiquitously, DNAJC19 acts as a component of the mitochondrial DNAJC19 complex that is responsible for the ATP-dependent translocation of select proteins from the inner mitochondrial membrane to the mitochondrial matrix. Defects in the DNAJC19 gene are the cause of 3-methylglutaconic aciduria type 5 (MGA5), otherwise known as dilated cardiomyopathy with ataxia (DCMA).

DnaK, originally identified for its DNA replication by bacteriophage l in E. coli is the bacterial hsp70 chaperone. This protein is involved in the folding and assembly of newly synthesized polypeptide chains and in preventing the aggregation of stress-denatured proteins. Dnak(residues 508-638) of the substrate binding domain is a-helical and appears to act as a lid covering the substrate binding cleft. DnaK(amino acid 508-638) was purified to apparent homogeneity by using conventional column chromatography techniques. Additional amino acid (Met) is attached at N- terminus.

Alpha crystallins are composed of two gene products ; alpha-A and alpha-B, for acidic and basic, respectively. Alpha crystallins can be induced by heat shock and are members of the small heat shock protein (sHSP also known as the HSP20). They act as molecular chaperones and hold them in large soluble aggregates. These heterogeneous aggregates consist of 30-40 subunits; the alpha-A and alpha-B subunits have a 3:1 ratio, respectively. Two additional function of -crystallins are an autokinase activity and participation in the intracellular architecture. The expression of alpha-A is preferentially restricted to the lens cell.

Alpha crystallins are composed of two gene products; alpha-A and alpha-B, for acidic and basic, respectively. Alpha crystallins can be induced by heat shock and are members of the small heat shock protein (sHSP also known as the HSP20). They act as molecular chaperones and hold them in in large soluble aggregates. These heterogeneous aggregates consist of 30-40 subunits; the alpha-A and alpha-B subunits have a 3:1 ratio, respectively. Two additional function of -crystallins are an autokinase activity and participation in the intracellular architecture. Alpha-B is expressed widely in many tissues and organs and occurs in many neurological diseases.

DNAJC15 which is expressed ubiquitously and located on the membrane contains 1 J domain. In many advanced cases of ovarian adenocarcinoma DNAJC15 is absent or down-regulated, due to hypermethylation and allelic loss. Loss of expression correlates with increased resistance to antineoplastic drugs, such as cisplatin. DNAJC15is a crucial component of the TIM23 translocase complex and stimulates the ATPase activity of HSPA9.

DsbE is a reducing Dsb protein involved in electron transfer for cytochrome c maturation in the periplasm of Escherichia coli. DsbE is one of 12 proteins required for their assembly in the periplasm. DsbE functions is to decrease disulphide bonds formed among correctly paired cysteine residues in the cytochrome c apoproteins prior to haem attachment by CcmF and CcmH.