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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.

APOM is belongs to the lipocalin protein family and is associated with high density lipoproteins and to a lesser extent with low density lipoproteins and triglyceride-rich lipoproteins. APOM is secreted through the plasma membrane but remains membrane-bound, where it takes part in lipid transport.

OTOR proteins is also known as fibrocyte-derived protein (Fdp) and Melanoma inhibitory activity-like (MIAL). Otoraplin is a member of the melanoma-inhibiting activity gene family. Otoraplin is a secreted 16 kDa globular protein that is expressed in the inner ear by periotic mesenchyme and developing and mature fibrocytes. OTOR is highly homologous to MIA/cartilage-derived retinoic acid-sensitive protein (CD-RAP), which is a cartilage-specific protein that is also expressed in malignant melanoma cells. The 111 amino acid mature human otoraplin contains 1 SH3 domain (46 – 107 amino acids) and a Tyr at position 50 that is reportedly sulfated. Otoraplin takes pasrt in the initiation of periotic mesenchyme chondrogenesis.
Otoraplin is secreted through the Golgi apparatus and plays a role in cartilage development and maintenance. A frequent polymorphism in the translation start codon of OTOR can abolish translation and may be associated with forms of deafness.

Prefoldin subunit 2 (PFDN2) belongs to the prefoldin beta subunit family. The PFDN2 protein is one of 6 subunits of prefoldin, which is a molecular chaperone complex that binds and stabilizes newly synthesized polypeptides, thus allowing them to fold correctly. PFDN2 binds specifically to cytosolic chaperonin (c-CPN) and transfers target proteins to it. PFDN2 also binds to a nascent polypeptide chain and promotes folding in an setting in which there are many competing pathways for nonnative proteins.

HB-EGF is an EGF related growth factor which signals via the EGF receptor, and stimulates the proliferation of SMC (smooth muscle cells), fibroblasts, epithelial cells and keratinocytes. HB-EGF is expressed in various cell types and tissues, including vascular endothelial cells and SMC, macrophages, skeletal muscle, keratinocytes and particular tumor cells. HB-EGF’s ability to explicitly bind sulfate proteoglycans is dissimilar from other EGF-like molecules, and might be related to the enhanced mitogenic activity, relative to EGF, that HB-EGF exerts on smooth muscle cells.

Alpha-hemoglobin stabilizing protein (AHSP) is an erythroid-specific protein that acts as a chaperone to prevent the aggregation of A-hemoglobin during normal erythroid cell development. AHSP specifically protects free A-hemoglobin from precipitation in live cells and in solution. AHSP is expected to modulate pathological states of alpha-hemoglobin excess such as beta-thalassemia. Furthermore, AHSP promotes alpha globin chain stability in human erythropoiesis. In addition, the AHSP stabilizes the alpha-Hb chain, thus avoiding its precipitation and its ability to generate ROS, which is implicated in cell death. AHSP is expressed in blood and bone marrow. AHSP subunit is a monomer, it forms a heterodimer with free alpha-hemoglobin. On the other hand, AHSP does not bind beta-hemoglobin nor alpha2beta2 hemoglobin A. AHSP is downregulated in TSEs (transmissible spongiform encephalopathies).

Lipocalin-1 (LCN1) belongs to the lipocalin family of small secretory proteins. Lipocalins are extracellular transport proteins, which bind to various hydrophobic ligands. LCN1 protein is the principal lipid binding protein in tears and is overproduced in response to numerous stimuli including infection and stress. LCN1 is a marker for chromosome aneuploidy as well as an autoantigen in Sjogren's syndrome.

ETS homologous factor (EHF) is a part of the ESE subfamily of Ets transcription factors. Ets factors are an important kind of transcriptional regulators which take part in hema-topoiesis, angiogenesis, organogenesis, oncogenesis and specification of neuronal connectivity. EHF is expressed solely in a subset of epithelial cells, with highest expression noticed in glandular epithelium of the prostate, pancreas, salivary gland and trachea. EHF transactivates the c-Met promoter via 3 high affinity binding sites, which support the notion that EHF contribute to branching morphogenesis.

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.

FSTL1 protein resembles follistatin, an activin-binding protein. FSTL1 is an autoantigen associated with rheumatoid arthritis and it holds an FS section, a follistatin-like sequence having 10 conserved cysteine residues.

Anamorsin, ( CIAPIN) is a member of anamorsin family. CIAPIN mainly expressed in the cytoplasm of liver, pancreas and heart tissue cells and does not show any homology to known apoptosis regulatory molecules of the Bcl-2 or CASP families, or to signal transduction molecules. CIAPIN1 Expression is reliant on growth factor stimulation. It is a ubiquitously expressed protein, and when it is overexpressed, it grants apoptotic resistance.

Endoglin is a type I membrane glycoprotein located on cell surfaces and is part of the TGF beta receptor complex.
The protein consists of a homodimer of 180 kDA with disulfide links. It has been found on endothelial cells, activated macrophages, fibroblasts, and smooth muscle cells. Endoglin has been found to be part of the TGF-beta1 receptor complex. It thus may be involved in the binding of TGF-beta1, TGF-beta3, activin-A, BMP-2, and BMP-7. Beside TGF-beta signaling endoglin may have other functions. It has been postulated that endoglin is involved in the cytoskeletal organization affecting cell morphology and migration. Endoglin has a role in the development of the cardiovascular system and in vascular remodeling. Its expression is regulated during heart development . Experimental mice without the endoglin gene die due to cardiovascular abnormalities.

Adiponectin is a hormone exclusively expressed from adipose tissue.
Many studies demonstrate that Adiponectin has direct anti-diabetic, anti-atherogenic and anti-inflammatory functions. APM-1 can increase insulin sensitivity of skeletal muscle. Attenuate hepatic lipogenesis and gluconeogenesis, regulate NO production in endothelial cells, inhibit proliferation of smooth muscle cells and prevent lipid accumulation of macrophage cells.
In the circulation, Adiponectin is present as three different oligomeric complexes, including the high molecular weight (HMW), the middle molecular weight (MMW, also called hexamer) and low molecular weigh (MMW, also called trimer) forms 8. Different oligomeric complex of Adiponectin activates different signaling pathways and exerts distinct functions.

Sprouty-Related EVH1 Domain Containing 1, also known as SPRED1, is a part of the Sprouty family of proteins and is phosphorylated by tyrosine kinase. SPRED1 inhibits growth-factor-mediated activation of MAP kinase. SPRED1 plays a role as a homodimer or as a heterodimer with SPRED2 to regulate activation of the MAP kinase cascade. SPRED1 is a negative regulator of hematopoiesis of bone marrow.

ETF is a heterodimer composed of alpha and beta subunit. ETFB protein is electron-transfer-flavoprotein, beta polypeptide that transports electrons between primary flavoprotein dehydrogenases involved in mitochondrial fatty acid and amino acid catabolism and the membrane-bound electron transfer flavoprotein ubiquinone oxidoreductase.

EYA2 belongs to tyrosine phosphatase family which specifically dephosphorylates 'Tyr-142' of histone H2AX (H2AXY142ph). EYA2 promotes effective DNA mending by dephosphorylating H2AX, promoting the enlistment of DNA repair complexes having MDC1. EYA2 role as histone phosphatase can explain its part in transcription regulation during organogenesis.

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.

Plasma protease C1 inhibitor (SERPING1) is a part of the serpin superfamily of serine protease inhibitors. SERPING1 plays an important role in regulating activation of both the complement and contact systems. That isdue to the fact that SERPING1 regulates the activation of complement factor C1 in addition to the activity of activated C1 by coupling with the active catalytic site at the light chains of C1r and C1s. SERPING1 insufficiency results in hereditary angioedema, which is characterized by recurrent episodes of localized angioedema of the skin, gastrointestinal mucosa or upper respiratory mucosa.

EED is a part of the Polycomb-group family whose members form multimeric protein complexe that are involved in preserving the transcriptional repressive state of genes over successive cell generations. EED mediates repression of gene activity through histone deacetylation, and acts as a specific regulator of integrin function. EED protein interacts with enhancer of zeste 2, the cytoplasmic tail of integrin ?7, immunodeficiency virus type 1 (HIV-1) MA protein, and histone deacetylase proteins.

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.

Eukaryotic translation elongation factor 1 delta (EEF1D) is a subunit of the elongation factor-1 complex that is responsible for the enzymatic transport of aminoacyl tRNAs to the ribosome. EEF1D functions as guanine nucleotide exchange factor. EEF1D interacts with HIV-1 Tat, and consequently represses the translation of host-cell, but not HIV-1, mRNAs. EEF1D overexpression is linked to oesophageal carcinoma and may negatively influence the outcome of medulloblastomas.

Ankyrin Repeat Family A2, also known as ANKRA2 contains 5 ANK repeats. ANKRA2 assist endocytosis by linking megalin to components of the cytoskeleton or endocytic machinery.