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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.

Cystatin E/M or CST6 is part of the cystatin type 2 family. Part of the cystatin type 2 family members can act as cysteine protease inhibitors, whereas cystatin E/M regulates cathepsin B inhibitors and not cathepsin C. cystatin E/M is a protein the when secreted, has an effect on osteogenesis and bone resorption, insulin regulation, response to systemic inflammation & hepatocyte growth factor receptors.

Decorin (DCN) is a small cellular or pericellular matrix proteoglycan which is closely related in structure to biglycan protein. Decorin is a secreted protein which binds to collagen and fibronectin in extracellular matrix. Decorin appears in different glycoforms, substituted with chondroitin sulfate or dermatan sulfate consistent with the original tissue. DCN contains one attached glycosaminoglycan chain. Decorin influences the rate of fibril formation. Decorin is capable of suppressing the growth of various tumor cell lines. DCN gene defects cause corneal dystrophy. The DCN gene is a candidate gene for Marfan syndrome.

ASCC1 is a subunit of the triggering signal cointegrator 1 (ASC-1) complex which is a transcriptional coactivator. ASC-1 complex takes a vital part in gene transactivation using various transcription factors such as activating protein 1 (AP-1), nuclear factor kappa-B (NF-kB) and serum response factor (SRF). ASCC1 has an N-terminal KH-type RNA-binding motif, essential for AP-1 transactivation by the ASC-1 complex. Alterations in ASCC1 result in Barrett esophagus and esophageal adenocarcinoma.

FAS or tumor necrosis factor receptor superfamily member 6 or TNFRSF6, is part of the death receptor family, which is part of the TNF receptor protein family. TNFRSF6 has a crucial part in regulating viral infections. FAS protein can be found in almost all cell types, when its cognate ligand (FasL) can be found in activated T cells, NK cells & dendritic cells. The regulating protein of FasL & TRAIL on HCMV-infected dendritic enhances direct destruction of activated T lymphocytes. furthermore, subvertneutrophil function in HCMV retinitis can occur when FasL is activated in HCMV infected retinal pigment epithelial cells.

Inhibins are dimeric peptide hormones produced by female ovarian granulose cells and male Sertoli cells as well as a variety of other tissues. Inhibins have two isoforms, A and B, with the same alpha subunit but different beta subunits. Inhibin A is a dimer of alpha and beta A subunits, inhibin B is a dimer of alpha and beta B subunits.
Inhibins are thought to inhibit the production of follicle-stimulating hormone (FSH) by the pituitary gland. In addition, Inhibins are also thought to play a role in the control of gametogenesis, and embryonic and fetal development.

Carbohydrate Sulfotransferase 3 (CHST3) belong to sulfotransferase 1 family which iincludes 14 enzymes that all members are Golgi-localized type II membrane proteins. These enzymes utilizes 3'-phospho-5'-adenylyl sulfate (PAPS) as sulfonate donor to catalyze the transfer of sulfate to position 6 of the N-acetylgalactosamine (GalNAc) residue of chondroitin. CHST3 can also sulfate Gal residues of keratan sulfate and Gal residues in sialyl N-acetyllactosamine (sialyl LacNAc) oligosaccharides. CHST3 is expressed in heart, placenta, skeletal muscle and pancreas. CHST3 takes part in maintenance of naive T-lymphocytes in the spleen.

WAP four-disulfide core domain protein 2 (WFDC2) is a protease inhibitor, which belongs to the WFDC domain family. WFDC2 is effective with a broad range of proteases, e.g. aspartic, serine or thiol proteases. WFDC2 is expressed in several normal tissues, including the male reproductive system, regions of the respiratory tract and nasopharynx. WFDC2 may be involved in sperm maturation. WFDC2 is also highly expressed in a number of tumors cells lines, such ovarian, colon, breast, lung and renal cells lines.

The enzyme Arylsulfatase A, also known as cerebroside-sulfatase, is responsible to break down sulfatides. The main molecule that Arylsulfatase A breaks down is cerebroside 3-sulfate into cerebroside and sulfate. The enzyme is encoded by the ARSA gene in humans. Phosphate can form a covalent bond with the Arylsulfatase A’s active site 3-oxoalanine, thus, inhibits the protein.

TFPI2 takes part in the regulation of plasmin-mediated matrix remodeling. Inhibits trypsin, plasmin, factor VIIa/tissue factor and weakly factor Xa. TFPI2 doesn’t have any influence on thrombin.

Vacuolar protein sorting-associated protein 26A (VPS26A) is a vital element of the retromer complex, which is required to recover lysosomal enzyme receptors (IGF2R and M6PR) from endosomes to the trans-Golgi network. Furthermore, VPS26A is essential in the regulation of transcytosis of the polymeric immunoglobulin receptor (pIgR-pIgA). Expression analysis in yeast and mammalian cells reveal that VPS26A interacts directly with VPS35 that functions as the core of the retromer complex.

ZW10 Interacting Kinetochore Protein (ZWINT) is involved in kinetochore function. ZWINT is part of the MIS12 complex, which is essential for kinetochore formation and spindle checkpoint activity. ZWINT is localized to the cytoplasm during interphase and to kinetochores from late prophase to anaphase. ZWINT interacts with ZW10 (Zeste White 10) and regulates the association between ZW10 and kinetochores. ZWINT gene defects are linked with the pathogenesis of Roberts’s syndrome, an autosomal recessive disorder characterized by growth retardation due to premature chromosome separation.

ADP-ribosylation factor 3 (ARF3) belongs to the human ARF gene family. This family encodes small guanine nucleotide-binding proteins which stimulate the ADP-ribosyltransferase activity of cholera toxin and have a role in vesicular trafficking and as activators of phospholipase D. ARF3 functions as an allosteric activator of the cholera toxin catalytic subunit, an ADP-ribosyltransferase. ARF3 is involved in protein trafficking; may modulate vesicle budding and uncoating within the Golgi apparatus. The ARF3 gene is comprised of 5 exons and 4 introns.

CXCL14 is involved in immunoregulatory and inflammatory processes. BRAK protein is structurally related to the CXC (Cys-X-Cys) subfamily of cytokines. CXCL14 displays chemotactic activity for monocytes but not for lymphocytes, dendritic cells, neutrophils or macrophages. CXCL14 is involved in the homeostasis of monocyte-derived macrophages.

FGF8 is part of the fibroblast growth factor family. FGF family members have wide mitogenic and cell survival activities, and participate in a variety of biological processes, including embryonic development, cell growth, morphogenesis, tissue repair, tumor growth and invasion. FGF8 supports androgen and anchorage independent growth of mammary tumor cells. FGF8 over expression increases tumor growth and angiogensis. The adult expression of FGF-8 gene is restricted to testes and ovaries. FGF8 functions as an embryonic epithelial factor. FGF8 takes part in midbrain and limb development, organogenesis, embryo gastrulation and left-right axis determination.

The Trefoil Factor peptides (TFF1, TFF2 and TFF3) are stable secretory proteins expressed in the gastrointestinal tract (gastric mucosa), and are involved in intestinal mucosal defense and repair. TFF1 is an essential protein for normal differentiation of the antral and pyloric gastric mucosa and functions as a gastric-specific tumor suppressor gene. TFF1 is a stabilizer of the mucous gel overlying the gastrointestinal mucosa that provides a physical barrier against various noxious agents. TFF1 protects the mucosa from isults, stabilizes the mucus layer, & affects healing of the epithelium. TFF1 is commonly expressed in tumors. TFF1 is related with the cell membrane of MCF-7 cells. High levels of TFF1 and TFF2 are found in serum from inflammatory bowel disease.

Calumenin is a calcium-binding protein located in the endoplasmic reticulum (ER) and sarcoplasmic reticulum (SR) of mammalian tissues which plays a role in ER functions as protein folding and sorting. Calumenin belongs to a family of multiple EF-hand proteins (CERC) that include reticulocalbin, ERC-55, and Cab45 and the product of this gene. Calumenin binds 7 calcium ions having low affinity and takes part in such ER functions as protein folding and sorting.

KISS1 is a metastasis suppressor protein that suppresses metastases of melanomas and breast carcinomas without affecting tumorigenicity.KISS1 functions to inhibit chemotaxis and invasion, attenuating metastasis in malignant melanomas. KISS1 is involved in the regulation of cell-matrix adhesion. KISS1 plays a role in cytoskeletal reorganization. A polymorphism in the terminal exon of KISS1 mRNA results in two protein isoforms. Expression of KiSS1 is localized to specific regions of the hypothalamus in numerous species and is regulated by gonadal steroids and across the estrous cycle..KISS1 generates a c-terminally amidated peptide, metastin which functions as the endogenous ligand of the g-protein coupled receptor gpr54. Activation of the receptor inhibits cell proliferation and cell migration, key characteristics of tumor metastasis.

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. Human Galectin-7 belongs to the prototypical Galectins containing a single CRD, which is initially identified in human epidermis as a monomer. The Galectin-7 expression is induced by tumor suppressor protein p53 and associated with apoptosis. Galectin-7 is a pro-apoptotic protein which functions intracellularlly upstream of JNK activation and mitochondrial cytochrome c release. The correlation of Galectin-7 with the UV-induced apoptosis of keratinocytes presents a critical mechanism in the maintenance of epidermal homeostasis. Human Galectin-7 is localized in both nucleus and cytoplasm.

VCAM1 is a member of the Ig superfamily. It is a cell surface sialoglycoprotein expressed by cytokine activated endothelium. VCAM-1 contains 6 or 7 immunoglobulin domains, and is expressed on both large and small vessels only after the endothelial cells are stimulated by cytokines. The protein has a number of functions including the regulation of leukocyte migration, leukocyte endothelial cell adhesion and signal transduction and may play a role in a number of inflammatory diseases (artherosclerosis and rheumatoid arthritis).

Thyroglobulin (TG) represents one of the main autoantigenic targets in autoimmune thyroid disease of humans. TG is a large globular dimeric glycoprotein with a total molecular weight of 660 kDa, which occupies a key precursor role in the biosynthesis of the thyroid hormones. Approximately 75% of the total protein content of the thyroid follicle consists of TG. The thyroid gland uses the Thyroglobulin in order to produce the thyroid hormones thyroxine (T4) and triiodothyronine (T3). Thyroglobulin is produced by the thyroid epithelial cells (thyrocytes) which form spherical follicles. Thyroglobulin is subsequently secreted and stored in the follicular lumen.
Patients with Hashimoto's thyroiditis or Graves' disease, frequently develop antibodies against Thyroglobulin. Tg-specific antibodies help in the diagnosis of the above diseases, however they also may be present in apparently healthy euthyroid individuals. Blood Thyroglobulin levels can be used as a tumor marker for certain kinds of thyroid cancer, and the may also be elevated in cases of Graves' disease.

OVCA2 is a member of the UPF0483 family. Universally expressed, the OVCA2 expression is regulated by retinoids. OVCA2 cooperates with apoptosis-related protein Bag-1, which indicates that OVCA2 takes part in cell proliferation. OVCA2 is thought to perform as a serine-hydrolase due to its catalytic and structural characteristics. Additionally, OVCA2 is believed to be involved in tumor suppression because of its reduced expression in ovarian and other tumor cell lines.

Platelet factor-4 is a 70-amino acid protein that is released from the alpha-granules of activated platelets and binds with high affinity to heparin. Its major physiologic role appears to be neutralization of heparin-like molecules on the endothelial surface of blood vessels, thereby inhibiting local antithrombin III activity and promoting coagulation. As a strong chemoattractant for neutrophils and fibroblasts, PF4 probably has a role in inflammation and wound repair. Oncostatin-A is a member of the CXC chemokine family. Human PF4 is used for the proof of heparin-induced thrombocytopenia. Furthermore it is used as an inhibitor in the angiogenesis during tumor therapy.