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Ephrin A5 (EFNA5) is a part of the ephrin ligand family which binds the members of ephrin receptor subfamily of tyrosine kinases and stimulates contact-dependent bidirectional signaling into neighboring cells. EFNA5 is mainly expressed in human adult brain, heart, spleen, and ovary and human fetal brain, lung, and kidney.

AFP is normally synthesized in the liver, intestinal tract, and yolk sac of the fetus. Antibody to AFP has been shown to be useful in detecting hepatocellular carcinomas (HCC) and germ cell neoplasms, especially yolk sac tumors.

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.

FIS1 is part of the mitochondrial complex that promotes mitochondrial fission. FIS1 induces cytochrome C discharge from the mitochondrion to the cytosol, eventually leading to apoptosis. FIS1 participates in peroxisomal growth and division. The C terminus is required for mitochondrial localisation, while the N teminus is necessary for mitochondrial fission.

Streptavidin is a tetrameric protein secreted by Streptomyces avidinii which binds firmly to biotin. Streptavidin is widely used in molecular biology through its unique high affinity for the vitamin biotin. The dissociation constant (Kd) of the biotin-streptavidin complex is about ~10-15 mol/L. The strong affinity recognition of biotin and biotinylated molecules has made streptavidin one of the most important components in diagnostics and laboratory kits. The streptavidin/biotin system has one of the biggest free energies of association of yet observed for noncovalent binding of a protein and small ligand in aqueous solution (K_assoc = 10**14). The complexes are also extremely stable over a wide range of temperature and pH.

Furin is a member of the peptidase S8 family. Furin signifies the ubiquitous endoprotease activity within constitutive secretory pathwaysas well as capable of cleavage at the RX (K/R) R consensus motif.Furin is considered to be one of the proteases responsible for the activation of HIV envelope glycoproteins gp160 as well as gp140 and might take part in tumor progression. Among the diseases associated with FURIN are dementia, familial british and plague.

Fas apoptotic inhibitory molecule, also known as FAIM function as an inducible effector molecule which mediates Fas resistance produced by surface Ig engagement in B cells. In addition FAIM protects against death receptor-triggered apoptosis and regulates B-cell signaling and differentiation. Among the diseases associated with FAIM are hemorrhagic thrombocythemia, and food allergy.

Cofilin is a family of actin-binding proteins which disassembles actin filaments. It is a widely distributed intracellular actin-modulating protein that binds and depolymerizes filamentous F-actin and inhibits the polymerization of monomeric G-actin in a pH-dependent manner. It is involved in the translocation of actin-cofilin complex from cytoplasm to nucleus.

A natural cytotoxicity receptor (NCR) NKp46 has been shown to represent a novel NK cell-specific molecule involved in human NK cell activation. The natural cytotoxicity receptors (NCRs) are a recently characterized family of Ig-like activation receptors that appear to be major triggering receptors in tumor cell recognition. The three known NCRs include NKp46 and NKp30, which are expressed on circulating NKcells, and NKp44, which is expressed only on activating NK cells. NKp46 has been implicated in NK cell-mediated lysis of several autologous tumor cells, pathogen-infected cell lines and mononuclear phagocytes infected with an intracellular bacterium. The Lysis of tumor cells by NK-cells involves recognition by NKp46 of heparan sulfate moieties of membrane heparan sulfate proteoglycans. Furthermore, NKp46 is a surface receptor involved in NK-cell cell death by apoptosis. NKp46 has two extracellular Ig-like domains followed by a ~40 residue stalk region, a type I transmembrane domain, and a short cytoplasmic tail. The extracellular Ig-like domain of NKp46 (22-255aa) is purified by FPLC gel-filtration chromatography, after refolding of the isolated inclusion bodies in a redox buffer. In addition, engagement of the antigen with the monoclonal antibody stimulates intracellular calcium levels and the synthesis of cytokines. CD59 is an NKp46 coreceptor (by physical association) together they activate cytotoxicity of human NK-cells, their engagement results in tyrosine phosphorylation of CD3-zeta chains associated with NKp46. Reduced cell surface expression of NKp46 and other NK-cell receptors is linked to the impaired NK-cell cytolytic function in viremic HIV-1 infection.

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.

Milk fat globule-EGF factor 8 protein (Mfge8) is pleiotropic secreted glycoprotein which promotes mammary gland morphogenesis, angiogenesis, and tumor progression. Mfge8 has also an imperative role in tissue homeostasis and the prevention of inflammation. Mfge8 functions as a bridge between phosphatidylserine on apoptotic cells and Integrin alpha V beta 3 on phagocytes, leading to the clearance of apoptotic debris.

Vascular endothelial growth factor is an important signaling protein involved in both vasculogenesis and angiogenesis. As its name implies, VEGF activity has been mostly studied on cells of the vascular endothelium, although it does have effects on a number of other cell types (e.g. stimulation monocyte/ macrophagemigration, neurons, cancer cells, kidney epithelial cells ). VEGF mediates increased vascular permeability, induces angiogenesis, vasculogenesis and endothelial cell growth, promotes cell migration, and inhibits apoptosis. In vitro, VEGF has been shown to stimulate endothelial cell mitogenesisand cell migration. VEGF is also a vasodilator and increases microvascular permeability and was originally referred to as vascular permeability factor.
Elevated levels of this protein are linked to POEMS syndrome, also known as Crow-Fukase syndrome. Mutations in this gene have been associated with proliferative and nonproliferative diabetic retinopathy.

Lactoferrin is a glycoprotein that belongs to the transferrin family of iron binding proteins. It is found in human breast milk as well as most epithelial surface secretions including tears, nasogastric, saliva, and bronchial. Lactoferrin binds 2 molecules of iron with very high affinity. Lactoferrin inhibits bacterial growth by withholding iron, its N-terminal region is an antimicrobial peptide. Lactotransferrin acts synergistically with lysozyme to potentiate the activity of both proteins. The multifunctional protein lactoferrin has many physiological possible roles. It is often referred to as an innate defense protein and frequently serves as the first line of defense in protection against pathogens. It has been shown to have the ability to bind iron, it is a natural anti-bacterial, anti-fungal and anti-viral, it is an antioxidant and it also has immunomodulatory properties. It has many beneficial properties, which make it a good candidate for a number of product applications. Considerable research is currently going on to explain the various suggested biological functions of lactoferrin.

Natriuretic Peptide Precursor B acts as a cardiac hormone with a variety of biological actions including natriuresis, diuresis, vasorelaxation, and inhibition of renin and aldosterone secretion. It is thought to play a key role in cardiovascular homeostasis. Helps restore the body's salt and water balance. Improves heart function.

Endothelial cells express three different vascular endothelial growth factor (VEGF) receptors, belonging to the family of receptor tyrosine kinases (RTKs). They are named VEGFR-1 (Flt-1), VEGFR-2 (KDR/Flk-1), VEGFR-3 (Flt-4). Their expression is almost exclusively restricted to endothelial cells, but VEGFR-1 can also be found on monocytes, dendritic cells and on trophoblast cells. The flt-1 gene was first described in 1990. The receptor contains seven immunoglobulin-like extracellular domains, a single transmembrane region and an intracellular splited tyrosine kinase domain. Compared to VEGFR-2 the Flt-1 receptor has a higher affinity for VEGF but a weaker signaling activity. VEGFR-1 thus leads not to proliferation of endothelial cells, but mediates signals for differentiation. Interestingly a naturally occuring soluble variant of VEGFR-1 (sVEGFR-1) was found in HUVE supernatants in 1996, which is generated by alternative splicing of the flt-1 mRNA. The biological functions of sVEGFR-1 still are not clear, but it seems to be an endogenous regulator of angiogenesis, binding VEGF with the same affinity as the full-length receptor.

NDRG2 belongs to the N-myc downregulated gene family that is a part of the alpha/beta hydrolase superfamily. NDRG2 takes part in dendritic and neuronal cell differentiation and outgrowth and is found in large quantities in heart, dendritic cells, brain, salivary gland and skeletal muscle and in small quantities in kidney and liver. In Alzheimer Disease (AD)-affected patients NDRG2 is found in brain lesions and is believed to be related to the progression of AD.

F-Box Protein 6, also known as FBXO6, is a part of the F-box protein family which is characterized by a roughly forty amino acid motif, the F-box. The F-box proteins are one of the 4 subunits of the ubiquitin protein ligase complex called SCFs (SKP1-cullin-F-box) that operates in phosphorylation-dependent ubiquitination. The F-box proteins are divided into three categories: Fbws containing WD-40 domains, Fbls containing leucine-rich repeats, and Fbxs containing different protein-protein interaction modules or no recognizable motifs. FBXO6 is a part of the Fbxs category, and its C-terminal area is very similar to that of rat NFB42 (neural F Box 42 kDa) which is involved in the control of the cell cycle.

The GAGA factor is a sequence-specific DNA-binding protein, which participates in the regulation of the expression of a variety of different classes of genes in Drosophila such as many developmentally regulated genes, stress induced genes, and cell cycle regulated genes, as well as housekeeping genes. GAGA contains a C-terminal glutamine-rich domain and a highly conserved N-terminal POZ domain which reported to be involved in self-oligomerization in a number of other POZ domain containing proteins. In case of GAGA protein, the N-terminal POZ domain mediates the formation of oligomers both in vitro and in vivo.

TIPIN is a member of the CSM3 family. TIPIN protein is essential for normal advancement of S-phase and vital for cell existence after DNA damage or replication stress. TIPIN is specifically necessary for the ATR - CHEK1 pathway in the replication checkpoint induced by ultraviolet light.

Elongin B (Elob) is a subunit of the transcription factor B (SIII) complex. SIII complex is a general transcription elongation factor that increases the RNA polymerase II transcription elongation past template-encoded arresting sites. The SIII complex comprised of a transcriptionally active subunit (A) and 2 regulatory subunits (B and C). Subunit A is transcriptionally active and its transcription activity is enhanced by binding to the dimeric complex of the SIII regulatory subunits B and C. The von Hippel-Lindau tumor suppressor protein binds to elongin B and C and inhibits transcription elongation.

Alpha 1-microglobulin (A1M) is a lipocalin superfamily member (kernal lipocalins). A1M is a low molecular weight protein component of plasma. A1M is distributed in plasma and extravascular compartments of all organs. Alpha-1 Microglobulin is found in mammals, birds, amphibians and fish. The primary sites of A1M synthesis are the liver and the kidney. Around the opening of the lipocalin pocket three lysyl residues are situated; those residues carry yellow-brown modification derived from the binding and degradation of heme and kynurenin (a tryptophan metabolite). A1-Microglobulin’s reductase and dehydrogenase have broad biological substrate specificity properties due to its’ free cysteine side-chain which is located in a flexible loop. Alpha-1-microglobulin is glycosylated by three separate carbohydrate chains: two complex carbohydrates which are N-linked to asparagines at residues 17 and 96, and the other simple carbohydrate which is O-linked to threonine at position 5. The carbohydrates comprise 22% of the total molecular mass of the protein. The glycosylation varies between species. A1M exists in two forms- a free form and complexed to other macromolecules: in humans- complexed to immunoglobulin A (IgA), in rat- complexed to alpha-1-inhibitor-3. Free A1M is exceptionally heterogeneous in charge (therefore also known as protein HC), and is found tightly linked to a chromophore. The free Alpha-1-microglobulin is a monomeric protein composed of one 188 residue polypeptide and contains three cysteines, two of which (residues 75 and 173) form a conserved intra-molecular disulphide link. The chromophoric group is covalently bound to the free cysteine residue at position 34. A1M binds retinol as a major ligand, but this is probably distinct from its covalent chromophore. Half of all human plasma A1M (approximately 0.03mg/ml) forms a 1:1 complex with about 5% of plasma immunoglobulin A. The resulting macromolecular complexes’ molecular weight is 200000, and a plasma concentration of 0.3mg/ml. The complex can exhibit both antibody activity and affect many of the biological actions of free Alpha-1-microglobulin. Alpha-1-microglobulin was first discovered in pathological human urine. It was suggested that A1M might be involved in tissue defense against reactive oxygen species, oxidation by heme and kynurenin. Evidence also suggests that A1M functions in the regulation of the immune system. Other functions include: inhibition of stimulation of cultured lymphocytes by protein antigens; induction of cell division of lymphocytes, a mitogenic effect that can either be enhanced or inhibited by the action of other plasma components; inhibition of neutrophil granulocyte migration in vitro; and inhibition of chemotaxis.
Other functions include inhibition of stimulation of cultured lymphocytes by protein antigens; induction of cell division of lymphocytes, a mitogenic effect that can either be enhanced or inhibited by the action of other plasma components; inhibition of neutrophil granulocyte migration in vitro; and inhibition of chemotaxis.

Human chorionic gonadotropin (hCG) is a peptide hormone produced in pregnancy, that is made by the embryosoon after conception and later by the syncytiotrophoblast(part of the placenta). Its role is to prevent the disintegration of the corpus luteumof the ovaryand thereby maintain progesterone production that is critical for a pregnancy in humans. hCG may have additional functions, for instance it is thought that it affects the immune tolerance of the pregnancy. Early pregnancy testing generally is based on the detection or measurement of hCG.