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Clusterin also named Apolipoprotein J (APO-J) is a 75-80 kD disulfide-linked heterodimeric protein containing about 30% of N-linked carbohydrate rich in sialic acid but truncated forms targeted to the nucleus have also been identified.
The precursor polypeptide chain is cleaved proteolytically to remove the 22-mer secretory signal peptide and subsequently between residues 227/228 to generate the a and b chains. These are assembled in anti-parallel to give a heterodimeric molecule in which the cysteine-rich centers are linked by five disulfide bridges and are flanked by two predicted coiled-coil a-helices and three predicted amphipathic a-helices.
Across a broad range of species clusterin shows a high degree of sequence homology ranging from 70% to 80%. It is nearly ubiquitously expressed in most mammalian tissues and can be found in plasma, milk, urine, cerebrospinal fluid and semen.
It is able to bind and form complexes with numerous partners such as immunoglobulins, lipids, heparin, bacteria, complement components, paraoxonase, beta amyloid, leptin and others. Clusterin has been ascribed a plethora of functions such as phagocyte recruitment, aggregation induction, complement attack prevention, apoptosis inhibition, membrane remodeling, lipid transport, hormone transport and/or scavenging, matrix metalloproteinase inhibition.
A genuine function of clusterin has not been defined. One tempting hypothesis says that clusterin is an extracellular chaperone protecting cells from stress induced insults caused by degraded and misfolded protein precipitates.
Clusterin is up- or down regulated on the mRNA or protein level in many pathological and clinically relevant situations including cancer, organ regeneration, infection, Alzheimer disease, retinitis pigmentosa, myocardial infarction, renal tubular damage, autoimmunity and others.

Interleukin-22 (IL-22), also known as IL-10-related T cell-derived inducible factor (IL-TIF) was initially identified as a gene induced by IL-9 in mouse T cells and mast cells. Mouse IL-22 cDNA encodes a 179 amino acid residue protein with a putative 33 amino acids signal peptide that is cleaved to generate a 147 aa mature protein that shares approximately 79% and 22% aa sequence identity with human IL-22 and IL-10, respectively. IL-22 has been shown to activate STAT-1 and STAT-3 in several hepatoma cell lines and upregulate the production of acute phase proteins. IL-22 is produced by normal mouse T cells upon Con A activation. Mouse IL-22 expression is also induced in various organs upon lipopolysaccharide injection, suggesting that IL-22 may be involved in inflammatory responses. The functional IL-22 receptor complex consists of two receptor subunits, IL-22R (previously an orphan receptor named CRF2-9) and IL-10Rβ (previously known as CRF2-4), belonging to the class II cytokine recep

Wheat Gliadin and related gluten components from barley, rye and possibly oats can cause an abnormal immune response called Celiac disease which is a chronic gastrointestinal disorder. Celiac disease characteristics are flattening of the jejunal mucosa and intestinal lesions of variable severity in hereditarily inclined individuals. Even though Celiac disease is not a classic autoimmune disease it is related to anti-tissue transglutaminase antibodies and gliadin antibodies tests are most recommended in screening populations at risk for CD and other gluten-sensitive enteropathies. In the past, serologic tests for gliadin antibodies usually were not very precise and were not enough for accurate diagnosis due to missing deamidated epitopes within the authentic gliadin fraction traditionally used in diagnostic test kits. ProSpec's deamidated Gliadin isoform matches to the deamidated neo-epitopes, which in the natural antigen are formed by transglutaminase-mediated glutamine side chain deamidation.

The B7 proteins are crucial in the regulation of the adaptive immune system. Among them is NCR3LG1. NCR3LG1 is part of the B7 family and is expressed on tumor cells. NCR3LG1 Interaction with NKp30 protein results in cytotoxicity and natural killer cell activation.Humans and rats have a single NCR3LG1 gene; though, numerous B7H6 genes were detected in a single large cluster in the Xenopus genome. NCR3LG1, a ligand for the NK cell activating receptor NKp30, targest to produce CAR that targets multiple tumor types. NCR3LG1 is expressed on many primary human tumors, including leukemia, lymphoma and gastrointestinal stromal tumors, though it is not constitutively expressed on normal tissues.

Nicotinamide riboside kinase 2 (ITGB1BP3) is a member of the uridine kinase family and NRK subfamily. ITGB1BP3 catalyzes the phosphorylation of nicotinic acid riboside and nicotinamide riboside to create nicotinic acid mononucleotide and nicotinamide mononucleotide. ITGB1BP3 reduces laminin matrix deposition and cell adhesion to laminin, but not to fibronectin. ITGB1BP3 is involved in the regulation of PXN at the protein level and of PXN tyrosine phosphorylation. ITGB1BP3 also has a role in the regulation of terminal myogenesis.

FGL1 belongs to the fibrinogen family. Fibrinogen Like 1 is homologous to the carboxy terminus of the fibrinogen beta- and gamma- subunits which comprises the 4 conserved cysteines of fibrinogens and fibrinogen related proteins. FGL1 lacks the platelet-binding site, cross-linking region and a thrombin-sensitive site which are necessary for fibrin clot formation. Fibrinogen takes part in the development of hepatocellular carcinomas.

Beta-crystallin A4 (CRYBA4) is a member of the beta/gamma-crystallin family which are the dominant structural components of the vertebrate eye lens. Beta-crystallins construct aggregates of various sizes and are able to self-associate to form dimers or to form heterodimers with other beta-crystallins. The CRYBA4 gene being a beta acidic group member is part of a gene cluster with beta-B1, beta-B2, and beta-B3.

Cellular Repressor of E1A-Stimulated Genes 1 (CREG1) both activates and inhibits gene expression to stimulate cellular proliferation and hinder differentiation. CREG1 antagonizes transcriptional activation and cellular transformation by E1A. CREG1 shares partial sequence similarity with E1A and binds both the general transcription factor TBP and the tumor suppressor pRb in vitro. CREG1 contributes to the transcriptional control of cell growth and differentiation.

Follicular Dendritic Cell Secreted Protein (FDCSP) is a small secreted protein which is found in follicular dendritic cells. The FDCSP protein specifically binds to activated B cells, and serves as a regulator of antibody responses. In addition, FDCSP is assumed to contribute to tumor metastases by promoting cancer cell migration and invasion. FDCSP binds to the surface of B-lymphoma cells, but not T-lymphoma cells, which is consistent with a function as a secreted mediator acting upon B-cells. FDCSP is abundantly expressed in the tonsil, lymph node, and tracheam, having a strong expression in the prostate and a lower expression in the thyroid, stomach and colon.

S100A10 is a member of the S100 family of proteins contains two EF-hand calcium-binding motifs and is thought to be involved in the regulation of a number of cellular processes including cell cycle progression and differentiation. S100 proteins are localized either in the cytoplasm or the nucleus of a wide range of cells. There are at least 13 members in the S100 gene family, which are located as a cluster on chromosome 1q21. S100A10 may function in exocytosis and endocytosis.

S100A11 is a member of the S100 family of proteins which contains two EF-hand calcium-binding motifs and is thought to be involved in the regulation of a number of cellular processes including cell cycle progression and differentiation. S100A11 may function in motility, invasion and tubulin polymerisation. S100 proteins are localized either in the cytoplasm or the nucleus of a wide range of cells. There are at least 13 members in the S100 gene family, which are located as a cluster on chromosome 1q21. Chromosomal rearrangements and altered expression of S100A11 have been implicated in tumor metastasis.

Cystatins are a superfamily of cysteine proteinase inhibitors found in both plants and animals. They comprise a group of proteinase inhibitors, widely distributed in tissues and body fluids, and form tight complexes with cysteine proteases such as cathepsin B, H, L and S. Cystatin C, a secreted molecule of this family, is of interest from biochemical, medicine and evolutionary points of view. Cystatin C, with molecular weight of 13260 Da, is composed of 120 amino acids, lacks carbohydrate and has two disulfide bridges located near the carboxyl terminus. Cystatin C is increased in patients with malignant diseases, and is related to the insufficiency of renal function and appears to be a better marker than creatinine. On the other hand, low levels of cystatin C involve cause the breakdown of the elastic laminae and, subsequently, the atherosclerosis and abdominal aortic aneurysm.

Kallistatin (SERPINA4) inhibits human amidolytic and kininogenase activities of tissue kallikrein. This inhibition is attained by formation of an equimolar, heat- and SDS-stable complex between the inhibitor and the enzyme, and production of a small C-terminal fragment of the inhibitor as a result of cleavage at the reactive site by tissue kallikrein.

Synaptotagmin V, (SYT5) is a member of synaptotagmin family, which is a family of type III membrane proteins characterized by cytoplasmic repeats related to protein kinase C regulatory (C2) domains that are considered to bind calcium. Synaptotagmins function as negative regulators of vesicle fusion, allowing fusion in the attendance of calcium, and as calcium receptors or sensor molecules. Among the diseases associated with SYT5 are labyrinthitis, and thyroiditis.

T cell immunoreceptor with Ig and ITIM domains or TIGIT, is an immune receptor located on part of T cells and Natural Killer Cells(NK). TIGIT is also known as Vstm3 and WUCAM. The receptor can bind with high affinity to dendritic cells(DCs), CD155(PVR) on macrophages, etc., and it can bind with lower affinity to CD112(PVRL2). TIGIT can inhibit the cytotoxicity of Natural Killer Cells through its ITIM domain via antibodies against the interaction with PVR and the activity is directed. It has been show on research that TIGIT-Fc fusion molecule can have interaction with PVR on dendritic cells and elevate its IL-10 secretion level or lower the secretion on IL-12 under the stimulation of LPS, moreover, it can inhibit the activation of T cell in vivo.

Grancalcin is calcium-binding protein which is particularly abundant in human neutrophils. GCA is a member of the penta EF-hand (PEF) subfamily of EF-hand proteins, who also comprises calpain, sorcin, peflin, and ALG-2. GCA undergoes essential conformational changes upon binding of calcium, which subsequently exposes hydrophobic amino acid residues, that direct the protein to hydrophobic surfaces. GCA cooperates with L-plastin, a protein known to have actin bundling activity, which suggests that GCA has a part in the regulation of neutrophils adhesion.

Heat-stable enterotoxins (STa) are small, cysteine-rich peptides secreted by Escherichia coli that are able to induce diarrhea through the stimulation of an intestine-specific receptor-guanylyl cyclase known as STaR. Binding of STa to STaR induces a dramatic increase in the cGMP content of the cell; the increase, in turn, inhibits salt absorption and stimulates chloride secretion. This imbalance of ions is accompanied by a massive accumulation of water in the gut that gives rise to the diarrhea and dehydration characteristic of enterotoxin activity. The identification of a receptor for STa on intestinal brush border membranes suggested the existence of an endogenous activator, described guanylin, a 15-amino acid peptide purified from rat small intestine, as a potential ligand for the STaR. This peptide shares sequence similarity with STa; see also uroguanylin. The molecular cloning of the human and mouse cDNAs encoding guanylin was reported. The sequences demonstrated that guanylin is present at the C-terminal end of a larger precursor protein. Expression in mammalian cells indicated that the 94- amino acid proguanylin is inactive. The biologically active guanylin can be released by either chemical or enzymatic treatment of proguanylin. By Northern blot analysis and in situ hybridization, showed that expression of guanylin mRNA is restricted to cells of the intestinal epithelium, specifically the Paneth cells at the base of the small intestinal crypts. These results demonstrate that guanylin is an endogenous activator of STaR isolated a cDNA encoding an apparent precursor of guanylin from a human intestinal cDNA library. The mRNA was expressed at high levels in human ileum and colon. In the mouse, interspecific backcross analysis used to map the Guca2 gene to the distal half of mouse chromosome 4 in a region of homology with human chromosome 1p. By fluorescence in situ hybridization mapped the GUCA2 gene to human 1p35-p34 Guanylin is thought to modulate intestinal water/electrolyte transport in a paracrine mode reported the nucleotide sequence of the gene, the characteristics of its circulating molecular form, and its localization in enterochromaffin cells of the gut. The gene, approximately 2.6 kb in size, consists of 3 exons interrupted by 2 introns. The hormonal form of guanylin is a 94-amino acid peptide with a molecular mass of 10.3 kDa. Guanylin is synthesized by gut enterochromaffin cells as a prohormone of 115 amino acids and is processed to the molecular form of 94 amino acids circulating in the blood.

Galectins are a family of animal lectins with an affinity for beta-galactosides. This family has at least 14 identified members. Galectins share similarities in the CRD (the carbohydrate recognition domain). Galectins are synthesized as cytosolic proteins. Though localized principally in the cytoplasm and lacking a classical signal peptide, galectins can also be stimulated to secretion by non-classical pathways or alternatively targeted to the nucleus. Galectins are involved in modulating cell-cell and cell-matrix interactions. Galectin-8 is a tandem-repeat-type member of the galectin family, consisting of 2 CRDs attached by a linker peptide. Galectin-8 is greatly expressed in lung carcinomas, a number of forms of prostate carcinomas, in addition to other tumor cells. Galectin-8 attaches to a subset of cell surface integrins to modulate ECM-integrin interactions. Once immobilized, Galectin-8 promotes cell adhesion by ligation and clustering of cell surface integrin receptors. On the other hand, as a soluble ligand, Galectin-8 can inhibit cell adhesion.

Type 1 cystatins are also called stefins which function as intracellular thiol protease inhibitors. Cystatin-B protein is able to form a dimer stabilized by noncovalent forces, inhibiting papain and cathepsins l, h and b. CSTB protein protects proteases leakage from lysosomes. Mutations in Stefin-B gene cause primary defects in patients with progressive myoclonic epilepsy (EPM1), a degenerative disease of the central nervous system. CSTB is overexpressed & elevated in the serum of HCC patients. Cystatin-B in vivo has a polymeric structure which is sensitive to the redox environment. Cystatin-B inhibits bone resorption by down-regulating intracellular cathepsin K activity despite increased osteoclast survival. Protein and mRNA levels of stefin B are significantly lower in atypical benign meningiomas. Stefins-A & Stefin-B which belong to the type-1 Cystatins, are up-regulated in lung tumours and thus able to counteract harmful tumour-associated proteolytic activity. Human stefin-A & Stefin-B form amyloid fibrils. Copper binding by stefin-B reduces amyloid fibril formation. A number of alternatively spliced CSTB isoforms were recognized in patients with progressive myoclonus epilepsy. Decreased CSTB activity in EPM1 pathogenesis is controled by cathepsins through increased activity of cathepsin-S & cathepsin-L.

Cathepsin F ( CTSF) is a member of the peptidase C1 family. Cathepsins are papain familycysteine proteinases which are a main component of the lysosomal proteolytic system. The CTSF gene isubiquitously expressed, and it maps to chromosome 11q13, close to the gene encoding cathepsin W. CTSF plays a role in normal protein catabolism. CTSF involved in some degradative processes occurring in tumor progression since it is highly expressed in some cancer cell lines.

CXC chemokine ligand 16 (CXCL16) is a type I membrane protein, which contains a non-ELR motif-containing CXC chemokine domain in its extracellular region. Human and Mouse CXCL16 share a 70% a.a. sequence similarity within their chemokine domains and 49% overall a.a. sequence identity. Functional CXCL16 can be dropped from the cell surface as an approximately 35kDa soluble protein. CXCR6 is the functional receptor for CXCL16. CXCL16 functions as a scavenger receptor on macrophages, which specifically binds to OxLDL (oxidized low density lipoprotein), proposing that CXCL16 may be involved in pathophysiology such as atherogenesis. In addition, CXCL16 induces a strong chemotactic response and calcium mobilization. CXCL16 binds to CXCR6/Bonzo.

Serpin Peptidase Inhibitor, Clade B Member 3, also known as SERPINB3 is a papain-like cysteine protease inhibitor which modulates the host immune response versus tumor cells. SERPINB3 is a protein coding gene which acts as an inhibitor of UV-induced apoptosis by suppressing the activity of c-Jun NH(2)-terminal kinase (JNK1).