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Ku antigen consists of two polypeptides (70 kDa and 80 kDa; the p80 subunit is occasionally called p86). The Ku heterodimer provides DNA-binding and regulatory functions to DNA-dependent protein kinase which is a central enzyme for DNA recombination processes in eucaryotic cells. The Ku protein plays important roles in multiple nuclear processes including DNA repair, V(D)J recombination, telomere maintenance, and the regulation of specific gene transcription.
Antibodies to Ku were originally reported in scleroderma-polymyositis overlap syndrome (up to 20% of patients) but have also been detectable in about 20 % of patients with primary pulmonary hypertension (as a complication of overlap), in 5-10 % of SLE and MCTD patients, and in up to 20 % of patients with primary Sj?gren's syndrome.
In IIF using HEp-2 cells, Ku-positive sera yield a dense, fine granular pattern with nucleolar staining that is typical but not specific for anti-Ku. Detection of Ku antibodies by Western blot may bear false-negative results since the main reactive epitope on the p70/p80 heterodimer is conformation-dependent.

SPARC protein, or secreted protein acidic and rich in cysteine, or osteonectin or basement-membrane protein 40 is a protein that is coded by the SPARC gene in humans. It is a glycoprotein located in bones, that binds to calcium. The osteonectin is secreted from osteoblasts cells when boas are formed, mineralized and promotes the formation and creation of mineral crystals. Asides from calcium, it has been shown that this protein can also bind to collagen.

CXADR Like Membrane Protein or CLMP, part of the CTX family within the immunoglobulin superfamily, is a type 1 transmembrane peptide. CLMP is expressed in the placenta and small intensine, skeletal muscle, colon, lungs and heart. CLMP is located in junction complexes across endothelial and epithelial cells and can take part in cell adhesion. The protein has influence on development of obesity via adipocyte differentiation.

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.

GTP Cyclohydrolase I Feedback Regulator, also known as GCHFR, is a Protein coding gene which includes a homodimer. GCHFR binds and mediates tetrahydrobiopterin inhibition of GTP cyclohydrolase I. GCHFR also regulates phenylalanine metabolism in the liver and in the production of biogenic amine neurotransmitters and nitric oxide.

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.

Gastrokine-1 (GKN1) is a member of the gastrokine family. GKN1 has mitogenic activity and is involved in preserving the integrity of the gastric mucosal epithelium. GKN1 is down-regulated in human gastric cancer tissue in comparison to normal gastric mucosa. GKN1 is expressed in the stomach; however no expression is detected in cancer tissue or gastric cancer cell lines.

Sorcin (SRI) which is a 22kDa calcium-binding protein was originally identified in multidrug-resistant cells. Sorcin, which modulates excitation-contraction coupling in the heart, contributes to calcium homeostasis in the heart sarcoplasmic reticulum.

Ring Finger Protein 7, also known as RNF7, is an extremely conserved ring finger protein. RNF7 is a vital subunit of SKP1-cullin/CDC53-F box protein ubiquitin ligases that are a part of the protein degradation machinery important for cell cycle progression and signal transduction. RNF7 is a substrate of casein kinase II (CSNK2A1/CKII) and also interacts with it. The phosphorylation of RNF7 by CSNK2A1 promotes the degradation of IkappaBalpha (CHUK/IKK-alpha/IKBKA) and p27Kip1(CDKN1B).

CBFB beta subunit is a heterodimeric core-binding transcription factor that is part of the PEBP2/CBF transcription factor family which controls a host of genes particulary to hematopoiesis and osteogenesis. CBFB is a non-DNA binding regulatory subunit which increases DNA binding by alpha subunit.

Heterogeneous Nuclear Ribonucleoprotein K, also known as HNRNPK, is a part of the subfamily of ubiquitously expressed heterogeneous nuclear ribonucleoproteins (hnRNPs). HNRNPK takes part in p53/TP53 reaction to DNA damage, acting at the level of both transcription activation and repression. HNRNPK is located in the nucleoplasm and has 3 repeats of KH domains which bind to RNAs.

Yip1 Interacting Factor Homolog B (YIF1b) is a member of the YIF1 family.

HER-2/neu (erbB-2) encodes an 185-kDa orphan receptor tyrosine kinase that is constitutively active as a dimer and displays potent oncogenic activity when overexpressed. Herstatin, as the product of alternative HER-2 transcript, retains intron 8.
The herstatin mRNA is expressed in normal human fetal kidney and liver, but is at reduced levels relative to p185HER-2 mRNA in carcinoma cells that contain an amplified HER-2 gene. Herstatin appears to be an inhibitor of p185HER-2, because it disrupts dimers, reduces tyrosine phosphorylation of p185, and inhibits the anchorage-independent growth of transformed cells that overexpress HER-2.

Protein-c Receptor (PROCR) is a receptor for activated protein C, a serine protease activated by and involved in the blood coagulation pathway. The PROCR protein is an N-glycosylated type I membrane protein which enhances the activation of protein C. PROCR gene mutations are linked with venous thromboembolism and myocardial infarction, as well as with late fetal loss during pregnancy. In addition, PROCR may have a role in malarial infection and has been linked with cancer.

FABP7 is a brain fatty acid binding protein. Fatty acid binding proteins (FABPs) are a family of small, highly conserved, cytoplasmic proteins that bind long-chain fatty acids and other hydrophobic ligands. FABPs are are inovlved in fatty acid uptake, transport, and metabolism. FABP7 is expressed in radial glia by the activation of Notch receptors and binds DHA with the highest affinity among all of FABPs. FABP7 plays an important role in transport of hydrophobic ligand with potential morphogenic activity during cns development. FABP7 is required for the establishment of the radial glial fiber system in developing brain, a system that is necessary for the migration of immature neurons to establish cortical layers (by similarity).

E-selectin (SELE) is a part of a family of divalent cation-dependent carbohydrate-binding glycoproteins or adhesion molecules. E-selectin 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.

Transcription elongation factor A protein-like 1 (TCEAL1) is a member of the transcription elongation factor A (SII)-like (TCEAL) family, which may function as nuclear phosphoproteins that modulate transcription in a promoter context-dependent manner. TCEAL1 is involved in transcriptional regulation. TCEAL1 is expressed in all tissues, especially highly expressed in the heart, ovary, prostate and skeletal muscle.

FABP6 also called ileal fatty acid binding protein, is part of the small family of highly conserved, cytoplasmic proteins that bind long-chain fatty acids and other hydrophobic ligands. FABP6 cytosolic protein binds bile acid. FABP6 plays a role in fatty acid uptake, transport, and metabolism. FABP6 stimulates gastric acid and pepsinogen secretion. seems to be able to bind to bile salts and bilirubins.
FABP6 expression is restricted in the small intestine to the ileum where it is involved in the enterohepatic circulation of bile acids. Alternate transcription promoters generate 2 transcript variants, encoding a 128 aa and a 177 aa residue protein. Human FABP6 isoform 2 contains 128 amino acid residues and is acetylated on Ala2. FABP6 binds together fatty acids and bile acids and is directly involved in fatty acid transport and metabolism.

SKP1 is a F-box enzyme which functions as a substrate recognition component of the SCF ubiquitin ligase complex which controls the ubiquitination of proteins involved in cell cycle progression, signal transduction and transcription. SKP1 binds to proteins containing an F-box motif, such as cyclin F, S-phase kinase-associated protein 2, and other regulatory proteins involved in ubiquitin dependent proteolysis. SKP1 takes part in the control of beta-catenin levels and the activity of beta-catenin dependent TCF transcription factors. SKP1 serves as an adapter that links the F-box protein to CUL1 in the SCF complex.

Syntaxin-11 (STX11) belongs to the t-SNARE family. Syntaxin-11 regulates protein transport between late endosomes and the trans-Golgi network. STX11 interacts with the SNARE proteins SNAP-23 and VAMP. STX11 gene mutations are linked with familial hemophagocytic lymphohistiocytosis.

NK3 Homeobox1 (NKX3-1) is a homeobox-containing transcription factor, which binds preferentially the consensus sequence 5'-TAAGT[AG]-3' and may act as a transcriptional repressor. The NKX3-1 transcription factor functions as a negative regulator of epithelial cell growth in prostate tissue. NKX3-1 has an imperative role in normal prostate development, regulating proliferation of glandular epithelium and in the formation of ducts in prostate. In addition, NKX3-1 functions as a tumor suppressor controlling prostate carcinogenesis, as shown by its ability to inhibit proliferation and invasion activities of PC-3 prostate cancer cells. Abnormal expression of NKX3-1 is linked with prostate tumor progression.

Fibrinogen silencer-binding protein (FSBP), interacts with X11alpha. The X11alpha/FSBP complex send signals to the nucleus in order to repress glycogen synthase kinase-3beta promoter activity. X11alpha is a neuronal adaptor protein that interacts with the amyloid precursor protein (APP) via a centrally located phosphotyrosine binding domain to inhibit the production of Abeta peptide that is deposited in Alzheimer's diseased brains.