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Thymidylate synthase catalyzes the methylation of deoxyuridylate to deoxythymidylate using 5,10-methylenetetrahydrofolate as a cofactor which maintains the dTMP (thymidine-5-prime monophosphate) pool vital for DNA replication and repair. Thymidylate synthase plays an important role as a cancer chemotherapeutic agent. Thymidylate synthase is the primary site of action for 5-fluorouracil, 5-fluoro-2-prime-deoxyuridine, and several folate analogs.

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), and VEGFR-3 (Flt-4). Their expression is almost exclusively restricted to endothelial cells, but VEGFR-1 can also be found on monocytes. All VEGF-receptors have seven immunoglobulin-like extracellular domains, a single transmembrane region and an intracellular split tyrosine kinase domain. VEGFR-2 has a lower affinity for VEGF than the Flt-1 receptor, but a higher signalling activity. Mitogenic activity in endothelial cells is mainly mediated by VEGFR-2 leading to their proliferation. Differential splicing of the flt-1 gene leads to the formation of a secreted, soluble variant of VEGFR-1 (sVEGFR-1). No naturally occurring, secreted forms of VEGFR-2 have so far been reported. The binding of VEGF165 to VEGFR-2 is dependent on heparin.

Neurotrophic Receptor Tyrosine Kinase 2, also referred to NTRK2, is a tyrosine-protein kinase receptor which takes part in the development & the maturation of the central and the peripheral nervous systems through regulation of neuron survival, migration, proliferation, differentiation and synapse formation & plasticity. NTRK2 acts in learning and memory by regulating both short term synaptic function and long-term potentiation. The substrates that are known for the TRK family receptors are: SHC1, PI-3 kinase and PLC-gamma-1.

TNFAIP8 which is a part of the TNFAIP8 family acts as a negative mediator of apoptosis and takes part in tumor progression. TNFAIP8 suppresses the TNF-mediated apoptosis by inhibiting caspase-8 activity but not the processing of procaspase-8, resulting in inhibition of BID cleavage and activation of caspase-3.

TRAIL Receptor-1 (DR4) and TRAIL Receptor-2(DR5) are members of the TNFR superfamily of transmembrane proteins and contain a cytoplasmic "death domain", which is capable of activating the cell's apoptotic machinery. These receptors are activated by binding to either membrane anchored or soluble TRAIL/Apo2L.

SAA4 is a constitutively expressed protein which is a member of the SAA family. SAA4 is a major acute phase reactant and an apolipoprotein of the HDL complex. SAA4 is constitutively expressed only in humans and mice; it is connected almost completely with lipoproteins of the high density range. The physiological function of SAA4 is unknown, and its serum concentration has no association with those of other major apolipoproteins. SAA4 mRNA and protein occurrence in macrophage derived foam cells of coronary and carotid arteries implied a specific role of human SAA4 during inflammation including atherosclerosis.

SARS Coronavirus is an enveloped virus containing three outer structural proteins, namely the membrane (M), envelope (E), and spike (S) proteins. Spike (S)-glycoprotein of the virus interacts with a cellular receptor and mediates membrane fusion to allow viral entry into susceptible target cells. Accordingly, S-protein plays an important role in virus infection cycle and is the primary target of neutralizing antibodies.
It has recently been shown that SARS (severe acute respiratory syndrome) is caused by a human coronavirus. Human coronaviruses are the major cause of upper respiratory tract illness, such as the common cold, in humans. Coronaviruses are positive-stranded RNA viruses, featuring the largest viral RNA genomes known to date (27-31 kb). The first step in coronavirus infection is binding of the viral spike protein, a 139-kDa protein, to certain receptors on host cells. The spike protein is the main surface antigen of the coronavirus. The glycosilated spike protein (as well as the nucleocapsid protein) can be detected in infected cell culture supernatants with antisera from SARS patients.

GOT2 is a pyridoxal phosphate-dependent enzyme which is found in cytoplasmic and inner-membrane mitochondrial forms, GOT1 and GOT2. GOT2 participates in amino acid metabolism and the urea and tricarboxylic acid cycles. Both enzymes are homodimeric and demonstrate close homology.

Gltathione S-transferase PI 2, also known as GSTP2 is multifunctional enzyme which is involved in theprotection of cellular components against anti-cancer drugs or peroxidative stress. Furthermore, down regulation of GSTP2induces an increase of oxidative damage in the pyramidal cells of the CA1&CA3 regions as well as in the granular layer ofthe dentate gyrus, which at the end leads to structural and functional damage.

ANXA5 is a member of the annexin family of calcium-dependent phospholipid binding proteins which are involved in membrane-related activity along exocytotic and endocytotic pathways. ANXA5 is a phospholipase A2 and protein kinase C inhibitory protein with calcium channel properties and takes part in cellular signal transduction, inflammation, growth and differentiation. ANXA5 is an anticoagulant protein that acts as an indirect inhibitor of the thromboplastin-specific complex, which is involved in the blood coagulation cascade. ANXA5 regulates coagulability in the blood stream by binding to phosphatidylserine and sulfatide. ANXA5 protects sinsuoidal endothelial cells from ischemia reperfusion damage. ANXA5 is necessary for normal CFTR chloride channel activity.

AHSG (fetuin-A) which is a glycoprotein present in the serum, is synthesized by hepatocytes. AHSG is one of the fetuin class of plasma binding proteins. It is involved in a number of functions, such as endocytosis, brain development and the formation of bone tissue. It is usually present in the cortical plate of the immature cerebral cortex and bone marrow hemopoietic matrix, hence it has been postulated that it participates in the development of the tissues. Yet, its exact significance is still vague. AHSG promotes endocytosis, hold opsonic properties and influences the mineral phase of the bone. Affinity for calcium and barium ions has been shown.

FKBP6 is part of the immunophilin protein family, and is involved in immunoregulation and basic cellular functions involving protein folding and trafficking. FKBP6 is widely expressed in all tissues, FKBP6 is present at utmost levels in testis, liver, kidney, skeletal muscle and heart. Deletion of FKBP6 contributes to hypercalcemia and growth delay in Williams-Beuren syndrome.

BLMH is affiliate to the papain superfamily of the cysteine protease and the peptidase C1 family. BLMH is a cytoplasmic cysteinepeptidase usually found as a homohexamer. BLMH shields normal and malignant cells from the glycopeptide antitumor drug BLM. BLMH catalyzes the inactivation of the antitumor drug BLM (a glycopeptide) by hydrolyzing the carboxyamide bond of its B-aminoalaninamide moiety and in addition demonstrates general aminopeptidase activity.

PEBP1 (Phosphatidylethanolamine binding protein 1) belongs to the phosphatidylethanolamine-binding protein family and a serine protease inhibitor that inhibits thrombin, neuropsin. PEBP1 plays a key modulatory part in several protein kinase signaling cascades. PKC phosphorylates PEBP1, resulting in the release of Raf-1 and activation of MEK and ERK. PEBP1 is expressed in many tissues and implicated in the regulation of such physiological processes as membrane biosynthesis, spermatogenesis, neural development, and metastasis suppression.
PEBP1 binds ATP, opioids and phosphatidylethanolamine, however it has lower affinity for phosphatidylinositol and phosphatidylcholine. PEBP1 may also be involved in the function of the presynaptic cholinergic neurons of the CNS. PEBP1 increases the production of choline acetyltransferase although not acetylcholinesterase. Furtheremore, PEBP1 functions in potentially sequestering toxic compounds, including locostatin which may have harmful effects on cells.
Loss of PEBP1 expression may have a significant role as prognostic marker in Gastrointestinal stromal tumors. In addition, PEBP1 is found differentially expressed in the Wernicke's Area from schizophrenia patients. PEBP1 is also, an invasion suppressor protein in nasopharyngeal carcinoma.

S100A1 is a member of the S100 family of calcium binding proteins with EF-hand type Ca+2 binding motive. S100A1 (Calcium Binding Protein A1) is involved in the activation of sarcoplasmatic calcium release and the regulation of intermediate filament polymerization. S100A1 may function in stimulation of Ca2+-induced Ca2+ release, inhibition of microtubule assembly, and inhibition of protein kinase C-mediated phosphorylation. Reduced expression of S100A1 has been implicated in cardiomyopathies.
S100 proteins are localized either in the cytoplasm or the nucleus of a wide range of cells. There are at least 13 members in the S100 gene family, which are located as a cluster on chromosome 1q21.

CCR4-Not transcription complex, subunit 7 (CNOT7) is a ubiquitous transcription factor. CNOT7 is a component of the CCR4 complex which functions as a general transcription regulation complex. Furthermore, CNOT7 binds to an anti-proliferative protein, BTG1 (B-cell translocation protein 1), which negatively regulates cell proliferation.

Lymphotoxin alpha, a member of the tumor necrosis factor family, is a cytokine produced by lymphocytes. LTA is highly inducible, secreted, and exists as homotrimeric molecule. LTA forms heterotrimers with lymphotoxin-beta which anchors lymphotoxin-alpha to the cell surface. LTA mediates a large variety of inflammatory, immunostimulatory, and antiviral responses. LTA is also involved in the formation of secondary lymphoid organs during development and plays a role in apoptosis.

TNFR2 belongs to the TNF-receptor superfamily. TNFR2 is receptor with high affinity for TNFSF2/TNF-alpha and approximately 5-fold lower affinity for homotrimeric TNFSF1/lymphotoxin-alpha. TNFR2 mediates the majority of the metabolic effects of TNF-alpha. In addition, knockout studies in mice propose a role for TNFR2 in protecting neurons from apoptosis by stimulating antioxidative pathways. TNFR2 expression might have a significant role in the angiogenesis, tumor cell proliferation and metastasis of Invasive micropapillary carcinoma of the breast.
There are 2 types of soluble TNF receptors: sTNFR-I and sTNFR-II, which act to neutralize the biological activities of TNF alpha and TNF beta. The levels of these soluble receptors seem to increase as a result of shedding of the extracellular domains of the membrane bound receptors. High levels of soluble TNF receptors are found in the amniotic fluid of pregnant women. TNFR2 and TNFR1 form a heterocomplex which mediates the recruitment of 2 anti-apoptotic proteins, c-IAP1 and c-IAP2, which possess E3 ubiquitin ligase activity. IAPs’ function in TNF-receptor signaling is unknown; nevertheless, c-IAP1 is believed to potentiate TNF-induced apoptosis by the ubiquitination and degradation of TNF-receptor-associated factor 2, which mediates anti-apoptotic signals. Oxidative stress promotes TNFR1 and TNFR2 self-interaction, ligand-independent and enhanced ligand-dependent TNF signaling. TNF-a, TNFR1 and TNFR2 have roles in cellular differentiation. TNFR1 and TNFR2 function in cell type-specific renal injury.

TNFR2 belongs to the TNF-receptor superfamily. TNFR2 is receptor with high affinity for TNFSF2/TNF-alpha and approximately 5-fold lower affinity for homotrimeric TNFSF1/lymphotoxin-alpha. TNFR2 mediates the majority of the metabolic effects of TNF-alpha. In addition, knockout studies in mice propose a role for TNFR2 in protecting neurons from apoptosis by stimulating antioxidative pathways. TNFR2 expression might have a significant role in the angiogenesis, tumor cell proliferation and metastasis of Invasive micropapillary carcinoma of the breast.
There are 2 types of soluble TNF receptors: sTNFR-I and sTNFR-II, which act to neutralize the biological activities of TNF alpha and TNF beta. The levels of these soluble receptors seem to increase as a result of shedding of the extracellular domains of the membrane bound receptors. High levels of soluble TNF receptors are found in the amniotic fluid of pregnant women. TNFR2 and TNFR1 form a heterocomplex which mediates the recruitment of 2 anti-apoptotic proteins, c-IAP1 and c-IAP2, which possess E3 ubiquitin ligase activity. IAPs’ function in TNF-receptor signaling is unknown; nevertheless, c-IAP1 is believed to potentiate TNF-induced apoptosis by the ubiquitination and degradation of TNF-receptor-associated factor 2, which mediates anti-apoptotic signals. Oxidative stress promotes TNFR1 and TNFR2 self-interaction, ligand-independent and enhanced ligand-dependent TNF signaling. TNF-a, TNFR1 and TNFR2 have roles in cellular differentiation. TNFR1 and TNFR2 function in cell type-specific renal injury.

BID is a pro-apoptotic Bcl-2 protein having only the BH3 domain. In reaction to apoptotic signaling, BID interacts with another Bcl-2 family of cell death regulators, called Bax, they form a heterodimer resulting to the insertion of Bax into the outer mitochondrial membrane. Bax induces the opening of the mitochondrial voltage-dependent anion channel which lead to the release of cytochrome c and other pro-apoptotic factors from the mitochondria resulting in activation of caspases. BID is a mediator of mitochondrial damage induced by caspase-8 (CASP8). CASP8 cleaves BID, and the COOH-terminal part translocates to mitochondria where it triggers cytochrome c release. The major proteolytic product p15 BID releasea cytochrome c. Isoform 1, Isoform 2 and Isoform 4 induce ice-like proteases and apoptosis while Isoform 3 does not induce apoptosis.

Defensins (alpha & beta) are cationic peptides with a wide spectrum of antimicrobial activity which include a significant arm of the innate immune system. There are 6 human beta-defensins, BD-1, BD-2, BD-3, BD-4, BD-5 and BD-6 which are expressed on some leukocytes and at epithelial surfaces. In addition to their direct antimicrobial activities, beta-defensins can act as chemoattractants towards immature dendritic cells and memory T cells. Beta-defensins contain a 6-cysteine motif which forms 3 intra-molecular disulfide bonds.

Chemokine (C-C motif) ligand 2 (CCL2) is a small cytokine belongs to the CC chemokine family which is also known as monocyte chemotactic protein-1 (MCP-1). MCP 1 is found at the site of tooth eruption and bone degradation. In the bone, CCL2 is expressed by mature osteoclasts. CCL2 recruits immune cells, such as monocytes, to sites of tissue injury and infection. MCP 1is produced as a protein precursor containing signal peptide of 23 amino acids and a mature peptide of 76 amino acids. As with many other CC chemokines, CCL2 is located on chromosome 17 in humans. The cell surface receptors that bind CCL2 are CCR2 and CCR5.

Adenylate kinases play a role in regulating the adenine nucleotide composition within a cell by catalyzing the reversible transfer of phosphate groups among adenine nucleotides. There are 3 types of adenylate kinase isozymes, AK1, AK2, and AK3 in vertebrates. Expression of these isozymes are tissue-specific and developmentally regulated. AK2 is localized in the mitochondrial intermembrane space and is involved in apoptosis. AK2 is mutated in individuals with reticular dysgenesis.