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EPO a is a member of the EPO/TPO family and encodes a secreted, glycosylated cytokine composed of four alpha helical bundles. EPO a is found in the plasma and regulates red cell production by promoting erythroid differentiation and initiating hemoglobin synthesis. EPO a also has neuroprotective activity against a variety of potential brain injuries and antiapoptotic functions in several tissue types.

Ataxin 3 is otherwise known as Machado-Joseph disease protein 1. Machado–Joseph disease is a hereditary autosomal dominant neurodegenerative disorder. ATXN3 contains trinucleotide CAG repeats in the coding region, and the expansion of these repeats from the normal 13-36 to 68-79 causes the Machado-Joseph disease. ATXN3 is a poly-ubiquitin-binding protein whose cellular turnover is regulated by its catalytic activity.
In addition, ATXN3 is a proteasome-associated factor which mediates the degradation of ubiquitinated proteins. ATXN3 folds reversibly using a single intermediate; partial destabilization of ATXN3 by chemical denaturation causes the formation of fibrillar aggregates by the non-pathological variant.
Ataxin-3 interacts with the major histone acetyltransferases cAMP-response-element binding protein (CREB)-binding protein, p300, and p300/CREB-binding protein-associated factor and hinders transcription by these coactivators.

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.

Spermidine/Spermine N1-Acetyltransferase 2, also known as SAT2 catalyzes the acetylation of polyamines (Acetyl-CoA + an alkane-alpha,omega-diamine = CoA + an N-acetyldiamine).

Cytohesin-interacting protein, also known as CYTIP contains 2 leucine zipper domains as well as a putative C-terminal nuclear targeting signal. However, CYTIP does not contain any hydrophobic regions. In addition, CYTIP is expressed weakly in resting NK and T cells. It also modulates the activation of ARF genes by CYTH1.

SEPT5 is a member of the septin gene family of nucleotide binding proteins which were initially defined in yeast as cell division cycle regulatory proteins. Septins are extremely conserved in yeast, Drosophila, and mouse and seem to regulate cytoskeletal organization. Interference of septin function disrupts cytokinesis and results in high multinucleate or polyploid cells.

Neutrophil Cytosolic Factor 4 (NCF4) is a cytosolic regulatory factor of the superoxide-producing phagocyte NADPH-oxidase, which is a multicomponent enzyme system imperative for host defense. The NCF4 protein is preferentially expressed in cells of myeloid lineage. NCF4 interacts mainly with neutrophil cytosolic factor 2 (NCF2/p67-phox) to create a complex with neutrophil cytosolic factor (NCF1/p47-phox), which further interacts with the small G protein RAC1 and translocates to the membrane upon cell stimulation. This complex subsequently activates flavocytochrome b, the membrane-integratedcatalytic core of the enzyme system. The PX domain of the NCF4 protein can bind phospholipid products of the PI(3) kinase, suggesting its part in PI(3) kinase-mediated signaling events. The phosphorylation of the NCF4 protein negatively regulates the enzyme activity.

Chemokine (C-X-C motif) ligand 11 (CXCL11) is a small cytokine belonging to the CXC chemokine family that is also called Interferon-inducible T-cell alpha chemoattractant (I-TAC) and Interferon-gamma-inducible protein 9 (IP-9). It is highly expressed in peripheral blood leukocytes, pancreas and liver, with moderate levels in thymus, spleen and lung and low expression levels were in small intestine, placenta and prostate. Gene expression of CXCL11 is strongly induced by IFN-g and IFN-b, and weakly induced by IFN-a. This chemokine elicits its effects on its target cells by interacting with the cell surface chemokine receptor CXCR3, with a higher affinity than do the other ligands for this receptor, CXCL9 and CXCL10. CXCL11 is chemotactic for activated T cells. Its gene is located on human chromosome 4 along with many other members of the CXC chemokine family.

SNAP-25 is an necessary element of the core complex that is responsible for presynaptic vesicle trafficking. Thus, SNAP-25 is directly involved in the release of neurotransmitters and this protein exists as two alternative isoforms, SNAP25A and SNAP25B which differ by 9 amino acids in central portion of these proteins.

SRGN is identified as a hematopoietic cell granule proteoglycan. Proteoglycans stored in the secretory granules of various hematopoietic cells also hold a protease-resistant peptide core, and is vital for neutralizing hydrolytic enzymes. SRGN is related to the macromolecular complex of granzymes and perforin that acts as a intermediary of granule-mediated apoptosis.

BNIP1 belongs to the of the BCL2/adenovirus E1B 19 kd-interacting protein (BNIP) family. BNIP1 interacts with the E1B 19 kDa protein, which defends cells from virally-induced cell death. In addition, BNIP1 interacts with E1B 19 kDa-like sequences of BCL2 which is an additional apoptotic protector. Adding up, BNIP1 is implicated in vesicle transport into the endoplasmic reticulum. Alternative splicing results of BNIP1 in four protein products with identical N- and C-termini have been found.

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.

GH is a member of the somatotropin/prolactin family of hormones which play an important role in growth control. The gene, along with four other related genes, is located at the growth hormone locus on chromosome 17 where they are interspersed in the same transcriptional orientation; an arrangement which is thought to have evolved by a series of gene duplications. The five genes share a remarkably high degree of sequence identity. Alternative splicing generates additional isoforms of each of the five growth hormones, leading to further diversity and potential for specialization. This particular family member is expressed in the pituitary but not in placental tissue as is the case for the other four genes in the growth hormone locus. Mutations in or deletions of the gene lead to growth hormone deficiency and short stature.

Human Cystatin A (CSTA or Stefin A) belongs to family 1 of the cystatin superfamily, which is characterized by the lack of disulphide bonds and carbohydrates. CSTA is an intracellular inhibitor regulating the activities of cysteine proteases of the papain family such as Cathepsins B, H and L. Cystatin A has also been implicated in several disease states. Because of altered proteolytic state in cancer progression, CSTA may have a role in the proteolitic pathways.

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.

The fasting-induced adipose factor (FIAF, ANGPTL4, PGAR, HFARP) was identified as an adipocytokine up-regulated by fasting, by peroxisome proliferator-activated receptor agonists, and by hypoxia. At the protein level, in human and mouse blood plasma, FIAF was found to be present both as a native protein and in a truncated form. Differentiation of mouse 3T3-L1 adipocytes was associated with the production of truncated FIAF, whereas in human white adipose tissue and SGBS adipocytes, only the native FIAF could be detected. Interestingly, the truncated FIAF was produced by human liver.
Experimental data suggest that FIAF is mainly presented in human blood plasma in a truncated form (FIAF-S2), whose level is increased by fenofibrate treatment. Levels of both truncated and native FIAF showed marked inter individual variation but were not associated with body mass index and were not influenced by prolonged semistarvation.

Myeloid differentiation antigen Gr1 (Ly6G) is a GPI-anchored protein, which is briefly expressed on monocytes in the bone marrow. The level of the Ly6G expression in the bone marrow completely correlates with granulocyte differentiation and maturation. Ly6G ligation on murine neutrophils inhibits neutrophil recruitment, thus providing the first evidence of a function for the Ly6G molecule. Ly6G is seen primarily on neutrophils, also in a subgroup of eosinophils, differentiating pre-monocytes and plasmacytoid dendritic cells.

Chemokine (C-X-C motif) ligand 11 (CXCL11) is a small cytokine belonging to the CXC chemokinen family that is also called inducible T-cell alpha chemoattractant (I-TAC) and (IP-9). I-TAC is highly expressed in peripheral blood leukocytes, pancreas and liver, with moderate levels in thymus, spleen and lung and low expression levels were in small intestine, placenta and prostate. Gene expression of CXCL11 is strongly induced by IFN-g and IFN-b, and weakly induced by IFN-a. The I-TAC chemokine elicits its effects on its target cells by interacting with the cell surface chemokine receptor CXCR3, with a higher affinity than do the other ligands for this receptor, CXCL9 and CXCL10. I-TAC is chemotactic for activated T cells. The CXCL11 gene is located on human chromosome 4 along with many other members of the CXC chemokine family.

Myostatin (GDF-8), a member of the TGFbeta superfamily, is a potent and specific negative regulator of skeletal muscle mass. In serum, myostatin circulates as part of a latent complex containing myostatin propeptide and/or follistatin-related gene. The myostatin propeptide is known to bind and inhibit myostatin in vitro. This interaction is relevant in vivo, with a majority (>70%) of myostatin in serum bound to its propeptide. The myostatin propeptide is negative regulator of myostatin in vivo.

Dystroglycan 1 (DAG1) is a laminin binding component of the dystrophin-glycoprotein complex which provides a connection between the subsarcolemmal cytoskeleton and the extracellular matrix. The N-terminal domain of alpha-dystroglycan is secreted into the cerebrospinal fluid. The effect of DAG1 on the nervous system remains vague. The complete dystroglycan complex is expressed in a various tissues and has a role in processes such as laminin and basement membrane assembly, sarcolemmal stability, cell survival, peripheral nerve myelination, nodal structure, cell migration, and epithelial polarization. DAG1 is a candidate gene for the site of the mutation in autosomal recessive muscular dystrophies. The dramatic decrease of DAG1 in Duchenne muscular dystrophy leads to a loss of linkage between the sarcolemma and extracellular matrix, making muscle fibers more susceptible to necrosis.

Developmentally-regulated GTP-binding protein 1 (DRG1) is a member of the GTP1/OBG family. DRG1 has a role in cell proliferation and differentiation, as well as in apoptosis, proposing a role in tumor formation and metastasis. Expression of the DRG1 was considerably reduced in breast tumor cells, particularly in patients with lymph node or bone metastasis as compared to those with localized breast cancer. The DRG1 protein is expressed at high levels in the heart, kidney and skeletal muscle and at lower levels in the brain, liver, placenta, lung, colon and spleen.

EFNA1 belongs to the ephrin (EPH) family. The EPH subfamily is the biggest group of receptor protein kinases and they take part in vital nervous system function and development.

Nephroblastoma Overexpressed (NOV) which is encoded by the NOV gene is a part of the CCN (CTGF/CYR61/NOV) family. NOV takes part in reducing tumorgenicity and proliferation of certain cancer cell lines. NOV interacts with numerous proteins and is involved in both internal and external cell signaling. NOV is expressed in particular tumors, including Wilm’s tumor and most nephroblastomas and is also exerts proangiogenic activities.

Sclerostin (SOST) is a secreted glycoprotein with a C-terminal cysteine knot-like (CTCK) domain and sequence similarity to the DAN (differential screening-selected gene aberrative in neuroblastoma) family of bone morphogenetic protein (BMP) antagonists. Sclerostin functions as a negative regulator of bone growth, by inhibiting bone formation. SOST is widely expressed at low levels, with highest levels in the bone, cartilage, kidney, liver, bone marrow and primary osteoblasts differentiated for 21 days. SOST gene defects cause sclerosteosis and bone dysplasia.