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Complement Factor B, also known as CFB, encodes complement factor B which is a component of the alternative pathway of complement activation. Factor B circulates in the blood as a single chain polypeptide. Once the alternative pathway is activated it is cleaved by complement factor D yielding the noncatalytic chain Ba and the catalytic subunit Bb. The active subunit Bb is a serine protease which connects with C3b to form the alternative pathway C3 convertase. Also, Bb is involved in the proliferation of preactivated B lymphocytes, while Ba inhibits their proliferation.

The protein encoded by this gene is a member of the bone morphogenetic protein family which is part of the transforming growth factor-beta superfamily. The superfamily includes large families of growth and differentiation factors. Bone morphogenetic proteins were originally identified by an ability of demineralized bone extract to induce endochondral osteogenesis in vivo in an extraskeletal site. This particular family member plays an important role in the onset of endochondral bone formation in humans, and a reduction in expression has been associated with a variety of bone diseases, including the heritable disorder Fibrodysplasia Ossificans Progressiva. Alternative splicing in the 5' untranslated region of this gene has been described and three variants are described, all encoding an identical protein.

Alpha-cardiac actin belongs to the actin family which is comprised of three main groups of actin isoforms, alpha, beta, and gamma. The alpha actins are found in muscle tissues and are a major constituent of the contractile apparatus. Defects in the cardiac actin have been associated with idiopathic dilated cardiomyopathy (IDC) and familial hypertrophic cardiomyopathy (FHC).

The FGFs are a family of more than 20 small (~17–26 kDa) secreted peptides. The initial characterization of these proteins focused on their ability to stimulate fibroblast proliferation. This mitogenic activity was mediated through FGF receptors (FGFRs) 1, 2, or 3. A fourth closely related tyrosine kinase receptor (FGFR4) was able to bind the FGFs but did not lead to a mitogenic response.
FGFs modulate cellular activity via at least 5 distinct subfamilies of high-affinity FGF receptors (FGFRs): FGFR-1, -2, -3, and -4, all with intrinsic tyrosine kinase activity and, except for FGFR-4, multiple splice isoforms, and FGFR-5, which lacks an intracellular kinase domain. There is growing evidence that FGFRs can be important for regulation of glucose and lipid homeostasis. The overexpression of a dominant negative form of FGFR-1 in ? cells leads to diabetes in mice, which thus implies that proper FGF signaling is required for normal ? cell function and glycemia maintenance. FGFR-2 appears to be a key molecule during pancreatic development. Moreover, FGFR-4 has been implicated in cholesterol metabolism and bile acid synthesis.
FGF-19, has been shown to cause resistance to diet-induced obesity desensitization and to improve glucose, and lipid profiles in diabetic rodents. Since these effects, at least in part, are mediated through the observed changes in metabolic rates, FGF-19 can be considered as a regulator of energy expenditure.
FGF-21 is preferentially expressed in liver, but an exact knowledge of FGF-21 bioactivity and its mode of action have been lacking to date. FGF-21 is a potent activator of glucose uptake on adipocytes, protects animals from diet-induced obesity when overexpressed in transgenic mice, and lowers blood glucose and triglyceride levels when therapeutically administered to diabetic rodents.

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.

Ephrin-B3 (EFNB3) which belongs to the ephrin gene family is essential in brain development as well as in its maintenance. EFNB3 binds to, and induces the collapse of, commissural axons/growth cones in vitro. EFNB3 loosely binds Eph receptors located on bordering cells, leading to contact-dependent bidirectional signaling into neighboring cells. The EPH and EPH-related receptors comprise the largest subfamily of receptor protein-tyrosine kinases and are implicated in mediating developmental events, mostly in the nervous system.

PFDN6 is a subunit of the heteromeric prefoldin complex that chaperones developing actin and alpha- and beta-tubulin chains until they are transferred to the cytosolic chaperonin containing TCP1 (CCT) complex. PFDN6 binds specifically to cytosolic chaperonin (c-CPN), transfers target proteins to it and bind to developing polypeptide chain to promote folding in a setting where there are many competing pathways for nonnative proteins.

Peptidase Inhibitor 3, also referred to PI3, is neutrophil and pancreatic elastase-specific inhibitor of skin. The protein may prevent elastase mediated tissue proteolysis. PI3 has shown inhibition of alpha-4-beta-2/CHRNA2-CHRNB2 nicotinic acetylcholine receptor, a weak inhibition on Kv11.1/KCNH2/ERG1 and on the transient receptor potential cation channel subfamily V member 1.

Fructosamine 3 Kinase (FN3K) catalyzes the phosphorylation of fructosamines which may result in deglycation, the non-enzymatic reaction of glucose with primary amines followed by Amadori re-arrangement. Phosphorylation of fructosamines instigates metabolism of the modified amine and brings about the de-glycation of fructoselysine and of glycated proteins. A high concentration of glucose may affect non-enzymatic oxidation of proteins by reaction of glucose and lysine residues (glycation). Fructosamines, the proteins altered in this way, are less active or functional.

E-cadherin (uvomorulin, cell-CAM120/80) is a calcium dependent cell adhesion molecule expressed predominately in epithelial tissues. It plays an important role in the growth and development of cells via the mechanisms of control of tissue architecture and the maintenance of tissue integrity. Numerous studies have demonstrated that reduction and/or loss of Ecadherin expression in carcinomas correlates positively with the potential of these tumors for invasion and metastasis.

AGXT is expressed only in the liver and its protein is localized mostly in the peroxisomes, where it is involved in glyoxylate detoxification. Mutations in the AGXT gene, some of which alter subcellular targetting, have been linked to type I primary hyperoxaluria.

The cytokine Macrophage migration inhibitory factor (MIF) has been identified to be secreted by the pituitary gland and the monocyte/macrophage and to play an important role in endotoxic shock. MIF has the unique property of being released from macrophages and T cells in response to physiological concentrations of glucocorticoids. The secretion of MIF is tightly regulated and decreases at high, anti-inflammatory steroid concentration.

E-selectin which is also called Endothelial leukocyte adhesion molecule 1, ELAM1, ELAM belongs to a family of divalent cation-dependent carbohydrate-binding glycoproteins or adhesion molecules. Eselectin is expressed on the surface of endothelial cells and mediates the interaction of leukocytes and platelets with endothelial cells during an inflammatory response. E-selectin is present in single copy in the human genome and contains 14 exons spanning about 13 kb of DNA.

Annexin A10 (ANXA10) is a member of the annexin family of calcium-binding proteins that contains a few members which are described by a conserved core domain that binds phospholipids in a Ca2+-dependent manner, and a unique amino-terminal region, which may convene binding specificity. The ANXA10 protein contains 4 annexin domains and might be required in the regulation of cellular growth and signal transduction pathways throughout the cell.

a-Synuclein (amino acids 1-140), an acidic neuronal protein of 140 amino acids, is extremely heat-resistant and is natively unfolded with an extended structure primarily composed of random coils. a-synuclein has been suggested to be implicated in the pathogenesis of Parkinson’s disease and related neurodegenerative disorders, and more recently, to be an important regulatory component of vesicular transport in neuronal cells. Moreover, recent studies have shown that a-synuclein has chaperone activity and that this activity is lost upon removing its C-terminal acidic tail (amino acids 96-140).

Ephrin-B2 belongs to the ephrin (EPH) family. The ephrins and EPH-related receptors contain the largest subfamily of receptor protein-tyrosine kinases and have been associated with mediating developmental events, particularly in the nervous system and in erythropoiesis. Based upon their structures and sequence relationships, ephrins are allocated into the ephrin-A (EFNA) class, which are anchored to the membrane by a glycosylphosphatidylinositol linkage, and the ephrin-B (EFNB) class, which are transmembrane proteins. Ephrin-B2 binds to the EPHB4 and EPHA3 receptors.

Sclerostin Domain Containing 1 (SOSTDC1) belongs to the sclerostin family and an N-glycosylated, secreted protein with a C-terminal cystine knot-like domain. The SOSTDC1 protein acts as a bone morphogenetic protein (BMP) antagonist. Specifically, SOSTDC1 directly associates with BMPs, prohibiting them from binding their receptors, thus regulating BMP signaling throughout cellular proliferation, differentiation, and programmed cell death. SOSTDC1 may also be involved in the onset of endometrial receptivity for implantation/sensitization for the decidual cell reaction Enhances Wnt signaling and hinders TGF-beta signaling. In addition, SOSTDC1 directly antagonizes the activity of BMP2, BMP4, BMP6 and BMP7 in a dose-dependent manner.

Endothelial cell-specific molecule 1 (ESM1) is a proteoglycan secreted by endothelial cells (mostly in the human lung and kidney tissues) and its mRNA expression is regulated by inflammatory cytokines. ESM1 has potent implications in lung endothelial cell-leukocyte interactions. In addition, ESM1 expression is detected in various epithelia and in adipocytes. ESM1 is involved in angiogenesis and it also promotes angiogenic sprouting. ESM1 expression is upregulated by TNF alpha, IL1 beta, or lipopolysaccharide and downregulated by IFN gamma. Genetically engineered cells overexpressing ESM1 induce tumor formation, implying that ESM1 might be involved in the pathophysiology of tumor growth in vivo.

Geminin is a 25 kDa nuclear protein, which inhibits DNA replication and is degraded during the mitotic phase of the cell cycle. Geminin controls replication by binding to the licensing factor Cdt1, and is involved in neural differentiation. In addition, Geminin directly interacts with Six3 and Hox homeodomain proteins during embryogenesis and inhibits their functions. Geminin can also promote DNA replication. Geminin has 2 roles in 2 different stages of the cell cycle: Geminin is a negative regulator of DNA replication during the “S phase” of the cell cycle. Inhibition of Geminin during the “S phase” (by RNAi) results in an additional round of replication of portions of the genome. During the “M phase” of the cell cycle (mitosis) Geminin stabilizes the replication factor Cdt1 promoting DNA replication during the next cell cycle. Moreover, inhibition of Geminin during mitosis (by RNAi) causes destabilization of Cdt1 protein and impairment of DNA replication during the next cell cycle. Geminin thus guarantees that only one round of replication occurs during each cell cycle. It was discovered that Geminin is overexpressed in a number of malignancies and cancer cell lines. This maintains the concept that Geminin has also a positive role in DNA replication and cell cycle progression. Geminin accumulates through S, G2 and M phases of the cell cycle but is absent during the G1 phase. During the metaphase/anaphase transition of mitosis Geminin levels decrease.

Coagulation factor VIII participates in the intrinsic pathway of blood coagulation; factor VIII is a cofactor for factor IXa which, in the presence of Ca+2 and phospholipids, converts factor X to the activated form Xa. This gene produces two alternatively spliced transcripts. Transcript variant 1 encodes a large glycoprotein, isoform a, which circulates in plasma and associates with von Willebrand factor in a noncovalent complex. This protein undergoes multiple cleavage events. Transcript variant 2 encodes a putative small protein, isoform b, which consists primarily of the phospholipid binding domain of factor VIIIc. This binding domain is essential for coagulant activity. Defects in this gene results in hemophilia A, a common recessive X-linked coagulation disorder.

Coagulation factor VII is a vitamin K-dependent factor which is essential for hemostasis. It circulates in the blood as a zymogen which is later converted to an active form by factor IXa, factor Xa, factor XIIa, or thrombin by minor proteolysis. Upon activation of factor VII, a heavy chain with a catalytic domain and a light chain with 2 EGF-like domains are generated, and the two chains are held together by a disulfide bond. The presence of factor III and calcium ions further activates the coagulation cascade by converting factor IX to factor IXa and/or factor X to factor Xa. Alternative splicing of factor VII results in 2 transcripts. Defects in coagulation factor VII can cause coagulopathy. Coagulation factor VII initiates the extrinsic pathway of blood coagulation. Minor proteolysis converts factor VII to factor VIIa by factors Xa, XIIa, IXa, or thrombin. Factor VIIa also converts factor IX to factor IXa in the presence of tissue factor and calcium.

CFI cleaves and inactivates C3b and C4b. CFI is inactive without a cofactor such as the soluble factor H and C4b binding protein. CFI cleaves the alpha-peptide chain of C3b and C4b when these binds1 of the cofactors. This cleavage inactivates all of the complement activating functions of these proteins producing iC3b and iC4b.CFI cleaves the alpha chain of C3b twice and this releases a small fragment called C3f. CFI can cleave iC3b releasing C3c from C3dg in the presence of CR1.C4b is cleaved rapidly at 2 sites separating C4c from C4d.

Calnexin (CANX) belongs to the calnexin family of molecular chaperones. Calnexin is a calcium-binding, ER-associated protein that interacts briefly with newly synthesized N-linked glycoproteins, facilitating protein folding and assembly. Calnexin may also have a key role in the quality control of protein folding by retaining incorrectly folded protein subunits within the ER for degradation. Calnexin grants long-term protection of wild-type Shaker protein from ER-associated degradation. Polypeptide substrate recognition by Calnexin requires specific conformations of the Calnexin protein. Calnexin dwindles with aging and might contribute to a cytoprotection in an array of human age-related diseases.