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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.The protein coding region of the substrate binding domain of DnaK (amino acids 385-638) was amplified by PCR and cloned into an E. coli expression vector. The substrate binding domain of DNAK was purified to apparent homogeneity by using conventional column chromatography techniques. Additional amino acid (Met) is attached at N- terminus.

Chitinase is a digestive enzyme which breaks down glycosidic bonds in chitin. Due to chitin being a component of the cell walls of fungi and exoskeletal elements of some animals (including worms and arthropods), chitinases are usually found in organisms that either need to remake their own chitin or to dissolve and digest the chitin of fungi or animals. Chitinivorous organisms include many bacteria genuses such as Aeromonas, Bacillus, Vibrio, among others, which may be pathogenic or detritivorous. Chitinase expression is mediated by the NPR1 gene and the salicylic acid pathway, both of which are involved in resisting fungal and insect attack. Human chitinases appear in gastric juices. They are likely to be digestive chitinases, for catabolic activity. Chitinase activity is identified systemically in humans, in the blood, and possibly cartilage. Chitinase has been related to allergies, asthma in particular has been linked to enhanced chitinase expression levels, also dust mites and mold spores which are both chitin covered.

C1q is the first component of the classical pathway of complement activation. C1q along with the enzymatically active components C1r and C1s forms the C1 complex. When C1 binds to immunoglobulins in the form of immune complexes, it leads to activation of C1r and C1s proteases and a further activates the classical pathway of complement. C1q is a glycoprotein that belongs to the collectin family, having a molecular weight of about 410-462 kDa. C1q is a hexamer composed of globular heads attached to collagen-like triple-helix tails. The globular heads of C1q exclusively bind to the CH2 domain of IgG molecules or the CH3 domain of IgM. Each heavy chain of the immunoglobulin molecule contains a single binding site for C1q. Given that C1q must bind to no less than two heavy chains in order to alter its conformation and activate C1r and C1s, its activation follows only after binding to immunoglobulins in the form of immune complexes bound to multivalent antigens. C1q’s main physiological role is in the clearance of immune complexes and apoptotic bodies from the organism. Interruption of this process may lead to development of autoimmunity. Individuals with genetic deficiencies of C1q or other components of the classical pathway are at risk to develop SLE. C1q specifically binds to apoptotic bodies of human keratinocytes, vascular endothelial cells and lymphocytes. Complement components C1q and bound C3 mediate the clearance of apoptotic bodies. Hence, C1q may advance the clearance of autoantigens, avoiding stimulation of the immune system. Nonetheless, an extended exposition of the immune system to the neoepitope exposed on C1q molecules bound to immune complexes or apoptotic bodies could ultimately lead to an autoimmune response against C1q itself and to an altered complement function. C1q deficiency may also lead to disruption of the negative selection of autoreactive B cells. C1q along with other specific recognition proteins bind to the highly conserved lupus antigens (dsDNA and nuclear proteins) and activate the complement system. Autoantibodies against C1q (anti-C1q) are found in a number of autoimmune and infectious diseases like glomerulonephritis (GN) and lupus erythematosus (SLE), these antibodies are significant in clinical practice due to their negative predictive value.

NANOG is a multidomain homeobox transcription factor which functions to maintain the undifferentiated state of pluripotent stem cells. NANOG expression counteracts the differentiation-promoting signals induced by the extrinsic factors LIF, Stat3 and BMP. Once NANOG expression is downregulated, cell differentiation can proceed. Proteins which regulate NANOG expression include transcription factors Oct4, SOX2, FoxD3, and Tcf3 and tumor suppressor p53.

STIP1 is an adaptor protein that mediates the functions of HSP70 & HSP90 in protein folding. STIP1 supports the transfer of proteins from HSP70 to HSP90 by binding together HSP90 and substrate-bound HSP70. STIP1 stimulates the ATPase activity of HSP70 and inhibits the ATPase activity of HSP90, suggesting that it regulates both the conformations and ATPase cycles of these chaperones. STIP1 genetic variations are involved in regulating corticosteroid response in asthmatic subjects with reduced lung function.

Dickkopf-related protein 2 (DKK2) is a member of the dickkopf family, which has a vital role in vertebrate development, where they locally inhibit Wnt regulated processes such as antero-posterior axial patterning, limb development, somitogenesis and eye formation. In adults, Dkks are involved in bone formation and bone disease, cancer and Alzheimer disease. DKK2 contains 2 cysteine rich regions and is implicated in embryonic development through its interactions with the Wnt signaling pathway. DKK2 may function as either an agonist or antagonist of Wnt/beta-catenin signaling, depending on the cellular environment and the presence of the co-factor kremen 2. DKK2 protein activity is also controlled by binding to the Wnt co-receptor LRP6 (LDL-receptor related protein 6).

RUNX3 is part of the RUNX family that mediates the expression of genes which participate in cellular differentiation and cell cycle progression. RUNX3 heterodimer and the beta subunit form a complex that binds to the core DNA sequence 5''-PYGPYGGT-3'' found in several enhancers and promoters, and can either activate or suppress transcription. RUNX3 interacts with additional transcription factors. RUNX3 is a good candidate for gastric cancer tumor suppressor diagnosis.

Phosphatidylinositol transfer protein beta isoform (PITPNB) is found in the cytoplasm, where it catalyzes the transfer of phosphatidylinositol (PI) and phosphatidylcholine (PC) between membranes. PITPNB mobilizes PI from the endoplasmic reticulum and regulates its release from stored vesicles in the Golgi network. PITPNB is extensively expressed in various tissues.

Age-Related Maculopathy Susceptibility 2 or ARMS2 is a protein that is is being researches for its ability to take part in diseases in old age. Mutations in Age-Related Maculopathy Susceptibility 2 is related to age-caused molecular degeneration.

GDNF promotes the survival and differentiation of neurons in culture, and is able to prevent apoptosis of motor neurons induced by axotomy. The encoded protein is processed to a mature secreted form that exists as a homodimer. The mature form of the protein is a ligand for the product of the RET (rearranged during transfection) protooncogene. In addition to the transcript encoding GDNF, two additional alternative transcripts encoding distinct proteins, referred to as astrocyte-derived trophic factors, have also been described. Mutations in this gene may be associated with Hirschsprung disease.
GDNF enhances survival and morphological differentiation of neurons and increases their high-affinity uptake.

Activity-regulated cytoskeleton-associated protein (ARC) takes part in the regulation of cell morphology and cytoskeletal organization and is required for consolidation of synaptic plasticity as well as formation of long-term memory. ARC regulates endocytosis of AMPA receptors in response to synaptic activity and is also required for homeostatic synaptic scaling of AMPA receptors. ARC is required in the stress fiber dynamics and cell migration.

Kallikrein-3 (KLK3) is a part of the kallikrein-related peptidase family. Kallikreins are a subgroup of serine proteases having various physiological functions. Numerous kallikreins take part in carcinogenesis and some may be prospective cancer and other disease biomarkers. Kallikrein-3 is 1 of the 15 kallikrein subfamily members located in a cluster on chromosome 19 and is a protease present in seminal plasma. KLK3 hydrolyzes semenogelin-1 consequently leading to the liquefaction of the seminal coagulum. KLK3 acts normally in the liquefaction of seminal coagulum, probably by hydrolysis of the high molecular mass seminal vesicle protein. Serum level of the KLK3 protein, called PSA in the clinical setting, is beneficial in the diagnosis and monitoring of prostatic carcinoma.

PET117 is nuclear gene essential for the assembly of active cytochrome c oxidase in S. cerevisiae. Nevertheless the gene products are not subunits of the final assembled cytochrome c oxidase complex. PET117 is found in chromosome V proximate the HIS1 gene.

Adiponectin, also referred to as Acrp30, AdipoQ and GBP-28, is a recently discovered 244 amino acid protein, the product of the apM1 gene, which is physiologically active and specifically and highly expressed in adipose cells (Adipokine). The protein belongs to the soluble defense collagen super family; it has a collagen-like domain structurally homologous with collagen VIII and X and complement factor C1q-like globular domain. APM-1 forms homotrimers, which are the building blocks for higher order complexes found circulating in serum.

Ku antigen consists of two polypeptides (70 kDa and 80 kDa; the p80 subunit is occasionally called p86). The Ku heterodimer provides DNA-binding and regulatory functions to DNA-dependent protein kinase which is a central enzyme for DNA recombination processes in eucaryotic cells. The Ku protein plays important roles in multiple nuclear processes including DNA repair, V(D)J recombination, telomere maintenance, and the regulation of specific gene transcription.
Antibodies to Ku were originally reported in scleroderma-polymyositis overlap syndrome (up to 20% of patients) but have also been detectable in about 20 % of patients with primary pulmonary hypertension (as a complication of overlap), in 5-10 % of SLE and MCTD patients, and in up to 20 % of patients with primary Sj?gren's syndrome.
In IIF using HEp-2 cells, Ku-positive sera yield a dense, fine granular pattern with nucleolar staining that is typical but not specific for anti-Ku. Detection of Ku antibodies by Western blot may bear false-negative results since the main reactive epitope on the p70/p80 heterodimer is conformation-dependent.

Secreted Protein Acidic & Rich in Cysteine (SPARC) protein is coded by the SPARC gene in humans. SPARC is a glycoprotein located in bones that binds to calcium. SPARC is produced by fibroblasts, capillary endothelial cells, platelets and macrophages, mainly in areas of tissue morphogenesis and remodelling. Asides from calcium, SPARC can also bind to collagen.

FABP1 (Fatty acid binding protein1) encodes the fatty acid binding protein found in liver. FABP1 is composed of ten antiparallel beta strands that form a barrel with a bigger binding pocket than the other FABPs allowing it to accommodate two fatty acid. This protein binds free fatty acids and their coenzyme A derivatives, bilirubin, and some other small molecules in the cytoplasm; it may be involved in intracellular lipid transport and metabolism.

SPARC, an acronym for “secreted protein, acidic and rich in cysteine”, is also known as osteonectin or BM-40. It is the founding member of a family of secreted matricellular proteins with similar domain structure. The 303 amino acid, 43 kDa protein contains a 17 aa signal sequence, an N-terminal acidic region that binds calcium, a follistatin domain containing Kazal-like sequences, and a C-terminal extracellular calcium (EC) binding domain with two EF-hand motifs. SPARC is produced by fibroblasts, capillary endothelial cells, platelets and macrophages, especially in areas of tissue morphogenesis and remodeling. SPARC shows context-specific effects, but generally inhibits adhesion, spreading and proliferation, and promotes collagen matrix formation. For endothelial cells, SPARC disrupts focal adhesions and binds and sequesters PDGF and VEGF. SPARC is abundantly expressed in bone, where it promotes osteoblast differentiation and inhibits adipogenesis.

TNFSF15 is a cytokine that belongs to the tumor necrosis factor (TNF) ligand family. This protein is abundantly expressed in endothelial cells, but is not expressed in either B or T cells. The expression of TNFSF15 is inducible by TNF and IL-1 alpha. This cytokine is a ligand for receptor TNFRSF25 and decoy receptor TNFRSF21/DR6. It can activate NF-kappaB and MAP kinases, and acts as an autocrine factor to induce apoptosis in endothelial cells. TNFSF15 is also found to inhibit endothelial cell proliferation, and thus may function as an angiogenesis inhibitor. An additional isoform encoded by an alternatively spliced transcript variant has been reported but the sequence of this transcript has not been determined.

TRAF-interacting protein with FHA domain-containing protein A (TIFA) is an adapter protein that mediates the IRAK1 and TRAF6 interaction following IL-1 stimulation, triggering the downstream activation of NF-kappa-B and AP-1 pathways. The TIFA protein stimulates the oligomerization and polyubiquitination of TRAF6, leading to the activation of TAK1 and IKK through a proteasome-independent mechanism.

ASB13 belongs to the ankyrin repeat and SOCS box-containing (ASB) family of proteins which contains ankyrin repeat sequence and a SOCS box domain. ASB13 is a protein coding gene that plays a role as a substrate-recognition part of a SCF-like ECS E3 ubiquitin-protein ligase complex which arbitrates the ubiquitination and subsequent proteasomal degradation of target proteins.

Chromosome 10 Open Reading Frame 54, also known as C10ORF54 is part of the immunoglobulin superfamily. Like a transmembrane molecule, C10ORF54 is expressed in the bone on embryonic stem cells (ESCs), and on tumor cell surface as well. Accordingly, C10ORF54 supports the differentiation of ESC and ehhances BMP4 induced signaling in ESC, however C10ORF54 is also down regulated following to BMP4 exposure.

OX40 Ligandis a part of the tumor necrosis factor (TNF)receptor family. OX40L receptor is OX40 which is expressed predominantly on activated CD4+ T cells.OX40 Ligandis expressed on various antigen-presenting cells such asmacrophages, DC2sand activated Blymphocytes. Expression of OX40 is momentary following engagement of T cell receptors. The ligation of OX40-OX40L stimulates proliferation anddifferentiation of activated B cells,increases immunoglobulin secretion and is also a sourceof survival signal for T cells and enables the development of memory T cells.

SOD2 is part of the iron/manganese superoxide dismutase family. It encodes a mitochondrial protein that forms a homotetramer and binds one manganese ion per subunit. SOD2 binds to the superoxide byproducts of oxidative phosphorylation and converts them to hydrogen peroxide and diatomic oxygen. Mutations in SOD2 gene have been associated with idiopathic cardiomyopathy (IDC), premature aging, sporadic motor neuron disease, and cancer. SOD2 destroys radicals which are usually produced within the cells and which are toxic to biological systems.