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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.

UCHL1 (PGP9.5) belongs to a gene family whose products hydrolyze small C-terminal adducts of ubiquitin to produce the ubiquitin monomer. Protein Gene Product (PGP9.5) is a neuron specific protein, structurally and immunologically distinct from neuron specific enolase. Human UCHL1 and UCHL3 have an extremely complicated knot structure for a protein, with five knot crossings. It is considered that the knot structure may increase a protein''s resistance to degradation in the proteasome. The protein, which has a molecular weight of 27 kDa was first defined by high resolution two dimetional PAGE. Standard immunohistochemical techniques have demonstrated the presence of PGP9.5 in neurons and nerve fibers at all levels of the central and peripheral nervous system, in many neurodcrine cells, in segments of the renal tubules, in spermatogonia and leydig cells of the testis, in ova and in some cells of both the pregnant and non pregnant corpus luteum. A point mutation (I93M) in UCHL1 is implicat

Adiponectin is an important negative regulator in hematopoiesis and immune systems. It may be involved in ending inflammatory responses through its inhibitory functions. Inhibits endothelial nf-kappa-b signaling through a camp-dependent pathway. Inhibits tnf-alpha- induced expression of endothelial adhesion molecules. Involved in the control of fat metabolism and insulin sensitivity.

Adiponectin 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.

Erythropoietin receptor, also known as EPOR arbitrates erythropoietin-induced erythroblast proliferation as well as differentiation. During EPO binding, EPOR activates Jak2 tyrosine kinase which activates various intracellular pathways including: Ras/MAP kinase, phosphatidylinositol 3-kinase and STAT transcription factors. Furthermore, stimulated EPOR has a function in erythroid cell survival. Mutations in EPOR may possibly produce erythroleukemia and familial erythrocytosis. In addition, dysregulation of EPOR can affect on the growth of selected tumors.

L-Selectin belongs to a family of divalent cation-dependent carbohydrate-binding glycoproteins or adhesion molecules. The L-Selectin molecule is composed of various domains: one homologous to lectins, one to epidermal growth factor, and two to the consensus repeat units found in C3/C4 binding proteins.
L-selectin is expressed constitutively on lymphocytes, monocytes and granulocytes and interacts specifically with carbohydrate groups on activated endothelial cells. L-Selectin may be shed by proteolytic cleavage and circulating levels in biological fluids may be used as an indicator of various pathological conditions. L-Selectin is cleaved by ADAM17.
L-selectin works as a "homing receptor" for leukocytes to enter secondary lymphoid tissues via the high endothelial venules. Ligands present on endothelial cells will attach to leukocytes expressing L-selectin, which causes the leukocytes to become localized at that juncture. The receptor is also located on the cell surfaces of "naive" T cells, which have not yet encountered their particular antigen. This surface expression is lost following the cells activation.

S100A9 is part of the S100 family of proteins containing 2 EF-hand calcium-binding motifs. S100A9 protein is localized in the cytoplasm and/or nucleus of a wide range of cells, and participates in the regulation of several cellular processes such as cell cycle progression and differentiation. S100 genes include no less than 13 proteins which are localized as a cluster on chromosome 1q21. S100A9 is involved in the inhibition of casein kinase and altered expression of this protein is associated with the disease cystic fibrosis.

Midkine (MK) is the product of a retinoic acid responsive gene, MK, and is a member of a family of heparin binding factors. It contains 121 amino acid residues including 10 conserved cysteine residues, all of which appear to be disulphide linked.
Midkine is expressed during embryogenesis, showing an expression pattern that suggests functions in neurogenesis, cell migration, secondary organogenetic induction, and mesoderm-epithelial interaction.
The widespread downregulation of MK in the adult human is reverted in a number of cancers, in which polypeptides are able to act as both transforming growth factors and promoters of angiogenesis.
Midkine (MK), induces chemotaxis of human neutrophils and was found to trigger mobilization of intracellular calcium of these cells.
Midkine induces histamine release from rat peritoneal mast cells with a rapid response in a dose dependent manner.
Midkine is also a potent stimulator of collagen and glycosaminoglycan synthesis.

PPIases catalyze the cis-trans isomerization of proline imidic peptide bonds in oligopeptides and accelerate the folding of proteins. Cyclophilin-A is a cyclosporin binding-protein and may play a role in cyclosporin A-mediated immunosuppression. Cyclophilin-A can also interact with several HIV proteins, including p55 gag, Vpr, and capsid protein, and has been shown to be necessary for the formation of infectious HIV virions. Multiple pseudogenes that map to different chromosomes have been reported.

SERPINB5 (Maspin) is a tumor suppressor protein of the serine proteinase inhibitor family. Maspin plays a vital role in embryonic development through critical functions in cell adhesion. In addition, Maspin is present in normal breast and prostatic epithelial cells although down regulated in the particular carcinomas. SERPINB5 impedes the growth, invasion, and metastatic properties of mammary tumors as well as the invasive ability of pancreatic ductal adenocarcinoma cells. SERPINB5 being a breast tumor suppressor gene is a significant marker of the disease progression in breast neoplasms. Furthermore, high expression of maspin is linked to squamous cell carcinoma in non-small-cell lung cancer. Moreover, maspin expression has been directly linked with the biological aggressiveness of ovarian carcinoma. Maspin exhibits no serine protease inhibitory activity since it does not undergo the stressed to relaxed conformational transition typical of active serpins.

Serpin Peptidase Inhibitor, Clade C Member 1 (SERPINC1), which is a part of the serpin superfamily, is a plasma protease inhibitor. SERPINC1 inhibits thrombin and other activated serine proteases of the coagulation system, and regulates the blood coagulation cascade. SERPINC1 also inhibits Thrombin and Factors IXa, Xa and XIa. Deficiencies in SERPINC1 can cause ATIII deficiency, an autosomal dominant disease which might lead to a hereditary thrombophilia.

BRCA2 And CDKN1A Interacting Protein (BCCIP) is a nuclear protein with multiple interacting domains which remained conserved throughout the evolution. BCCIP is an important cofactor for BRCA2 in tumor suppression, and a modulator of CDK2 kinase activity via p21. BCCIP takes also part in the regulation of BRCA2 and RAD51 nuclear focus formation, doublestrand break-induced homologous recombination, and cell cycle progression.

EPGN is an EGF-related polypeptide growth factor that signals through the ErbB receptor-1. EPGN is produced in numerous tissues, including the testis, liver, heart and in certain tumor cells. EPGN is mitogenic for fibroblasts and epithelial cells. Human EPGN is originally synthesized as a glycosylated 14.7 kDa transmembrane precursor protein, which is processed by proteolytic cleavage to produce a mature soluble sequence.

Alpha-parvin (PARVA) belongs to the parvin family of actin-binding proteins. PARVA has a role in the regulation of cell adhesion, cytoskeleton organization, motility and survival as well as in ciliogenesis. Parvins are related with focal contacts and contain calponin homology domains which connect to actin filaments. PARVA is extensively expressed, with the highest levels in heart, skeletal muscle, kidney and liver.

C8, a component of the complement system consists of three polypeptides C8A, C8B and C8G and takes part in the formation of Membrane Attack Complex (MAC). Patients with C8 deficiency are exposed to several bacteria infections. C8G, a member of the lipocalin family and calycin superfamily, is a secreted protein that can bind retinol. C8G is created in the liver, monocytes and fibroblast and has a role in clearing pathogens from an infected host.

PECR is the main enzyme for a projected peroxisomal chain elongation pathway and is primarily expressed in kidney and liver.

PI3 is an elastase-specific protease inhibitor, which contains a WAP-type four-disulfide core (WFDC) domain, and is thus a member of the WFDC domain family. Most WFDC gene members are localized to chromosome 20q12-q13 in two clusters: centromeric and telomeric. PI3 belongs to the centromeric cluster.

Eosinophil lysophospholipase (CLC) acts on biological membranes to regulate the multifunctional lysophospholipids. CLC is a lysophospholipase expressed in eosinophils and basophils. CLC hydrolyzes lysophosphatidylcholine to glycerophosphocholine and a free fatty acid. The CLC protein may possess carbohydrate or IgE-binding activities. CLC is both structurally and functionally related to the galectin family of beta-galactoside binding proteins. CLC may be linked with inflammation and some myeloid leukemias.

Caltractin (CETN2) is a member of a family of calcium-binding proteins and is a structural component of the centrosome. CETN2 has a role in nucleotide excision repair via association with xeroderma pigmentosum group C protein, suggesting possible coupling of cell division and nucleotide excision repair.

Ang K1-3 is a proteolytic fragment of plasminogen containing the first three kringle structures. A specific inhibitor of endothelial cell growth and angiogenesis. More active relative to kringles 1-4. Ang K1-3 reduces endothelial cell proliferation and acts as a potent inhibitor of angiogenesis and tumor growth.

Yersinia enterocolitica is a Gram-negative bacillus-shaped bacterium, which is a member of the Enterobacteriaceae family. Y.Enterocolitica is motile at temperatures between 22-29°C, however becomes non-motile at normal human body temperature. Y. Enterocolitica infection causes the yersiniosis disease, which is an animal-borne disease occurring in humans, as well as in a various groups of animals such as cattle, deer, pigs, and birds. Yersinia enterocolitica is a heterogeneous group of strains, which are conventionally classified by bio-typing into six bio-groups on the basis of phenotypic characteristics, and by serotyping into more than 57 “O” serogroups, on the basis of their O (lipopolysaccharide or LPS) surface antigen. Five of the six biogroups (1B and 2–5) are considered as pathogens. Nevertheless, only a few of these serogroups have been linked with disease in either humans or animals. Strains which belong to serogroups O:3 (biogroup 4), O:5,27 (biogroups 2 and 3), O:8 (biogroup 1B), and O:9 (biogroup 2) are most frequently isolated worldwide from human samples. Still, the main Y. enterocolitica serogroup in many European countries is serogroup O:3 followed by O:9, whereas the serogroup O:8 is mostly detected in the United States.

Granulocyte/Macrophage Colony-Stimulating Factors are cytokines that act in hematopoiesis by controlling the production, differentiation, and function of 2 related white cell populations of the blood, the granulocytes and the monocytes-macrophages. CSF-1 induces cells of the monocyte/macrophage lineage. It plays a role in immunological defenses, bone metabolism, lipoproteins clearance, fertility and pregnancy.

NPPC is proteolytically managed to create a secreted hormone of the natriuretic peptide family. NPPC is vasoactive and natriuretic and controls the evolution and differentiation of cartilaginous growth plate chondrocytes.

The adipose tissue exclusively expresses and secretes Adiponectin (Acrp30). Acrp30 is involved in various physiological processes such as energy homeostasis, insulin sensitivity, hormonal processes, fatty acid metabolism and obesity.
Adiponectin circulates in the plasma. Decreased levels of Adiponectin are associated with insulin resistance and hyperinsulinemia, as seen in people with obesity insulin resistance, and diabetes type 2, whose plasma levels of adiponectin are reduced.
The modular structure of Acrp30 is comprised of N-terminal collagenous domain followed by a C-terminal globular domain.
Acrp30 also acts as a significant negative regulator in hematopoiesis and immune systems; it may be involved in ending inflammatory responses through its inhibitory functions. Adiponectin inhibits endothelial NF-kappa-b signaling through a cAMP-dependent pathway, it also inhibits TNF-alpha- induced expression of endothelial adhesion molecules.