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Nudix Type Motif 4 (NUDT4) regulates the turnover of diphosphoinositol polyphosphates. The turnover of these high-energy diphosphoinositol polyphosphates exemplifies a molecular switching activity with significant regulatory consequences. Molecular switching by diphosphoinositol polyphosphates may be a factor in regulating intracellular trafficking.

Parathyroid hormone (PTH), or parathormone, is secreted by the parathyroid glands as a polypeptide containing 84 amino acids. It acts to increase the concentration of calcium in the blood, whereas calcitonin (a hormone produced by the parafollicular cells of the thyroid gland) acts to decrease calcium concentration. PTH acts to increase the concentration of calcium in the blood by acting upon parathyroid hormone receptor in three parts of the body: In the bones- It enhances the release of calcium from the large reservoir contained in the bones. Bone resorption is the normal destruction of bone by osteoclasts, which are indirectly stimulated by PTH. Stimulation is indirect since osteoclasts do not have a receptor for PTH; rather, PTH binds to osteoblasts, the cells responsible for creating bone. Binding stimulates osteoblasts to increase their expression of RANKL, which can bind to osteoclast precursors containing RANK, a receptor for RANKL. The binding of RANKL to RANK stimulates these precursors to fuse, forming new osteoclasts which ultimately enhances the resorption of bone. In the kidney- It enhances active reabsorption of calcium from distal tubules and the thick ascending limb. In the intestine- It enhances the absorption of calcium in the intestine by increasing the production of vitamin D and upregulating the enzyme responsible for 1-alpha hydroxylation of 25-hydroxy vitamin D, converting vitamin D to its active form (1,25-dihydroxy vitamin D) which effects the actual absorption of calcium (as Ca2+ ions) by the intestine via calbindin.

Tyrosylprotein Sulfotransferase 1, also known as TPST1 is the enzyme which catalyzes the sulfation reaction of protein tyrosines, a post-translational modification of proteins. TPST1 belongs to the protein sulfotransferase family. In addition, TPST1 utilizes 3'-Phosphoadenosine-5'-phosphosulfate (PAPS) as the sulfonate donor and also binds proteins with target tyrosine residues to eventually form the tyrosine O-sulfate ester group in addition to the desulfonated 3’-phosphoadenosine-5’-phosphate.

GAPDH is a catalytic enzyme normally known to play a role in glycolysis. GAPDH exists as a tetramer composed of 36-kDa subunits and has a range of intracellular functions. GAPDH catalyzes the reversible reduction of 1,3-bisphosphoglycerate to glyceraldehyde 3-phosphophate in the presence of NADPH. Besides functioning as a glycolytic enzyme in cytoplasm, GAPDH has function in intracellular processes such as membrane fusion, microtubule bundling, phosphotransferase activity, nuclear RNA export, DNA replication and DNA repair. GAPDH catalyzes a vital energy-yielding step in carbohydrate metabolism, the reversible oxidative phosphorylation of glyceraldehyde-3-phosphate in the presence of inorganic phosphate and nicotinamide adenine dinucleotide (NAD). The enzyme exists as a tetramer of identical chains.

Pyruvate kinase is a key enzyme in the glycolytic pathway. The M2 isoenzyme of pyruvate kinase is specifically expressed at high levels in tumor cells, and can be measured in plasma of patients with advanced breast cancer. The marker is useful for measuring disease activity, sensitivity to chemotherapy and recurrence.

Hexokinases phosphorylate glucose to produce glucose-6-phosphate, thus committing glucose to the glycolytic pathway. Hexokinase 2 is the predominant form found in skeletal muscle. It localizes to the outer membrane of mitochondria. Expression of this gene is insulin-responsive, and studies in rat suggest that it is involved in the increased rate of glycolysis seen in rapidly growing cancer cells.

NUDT1 is an enzyme that hydrolyzes oxidized purine nucleoside triphosphates, such as 8-oxo-dGTP, 8-oxo-dATP, 2-hydroxy-dATP, and 2-hydroxy rATP, to monophosphates, thereby preventing misincorporation of 8-oxo-dGTP into DNA thus preventing A:T to C:G transversions. NUDT1 is found mostly in the cytoplasm, with some in the mitochondria, suggesting that it is involved in the sanitization of nucleotide pools both for nuclear and mitochondrial genomes. Moreover, NUDT1 is expressed at much higher levels in proliferating cells than in resting cells. Misincorporation of oxidized nucleoside triphosphates into DNA/RNA during replication and transcription can cause mutations which may result in carcinogenesis or neurodegeneration.

Protein tyrosine phosphatase type IVA 1 (PTP4A1) is a cell signaling molecule that has regulatory roles in a variety of cellular processes. PTP4A1 is a unique nuclear PTP which is induced in regenerating liver and mitogen stimulated cells. PTP4A1 is primarily expressed in the spleen, bone marrow, thymus, lymph nodes, T lymphocytes and tonsil and is overexpressed in tumor cell lines.

Translational activator of mitochondrially encoded cytochrome c oxidase I (TACO1) belongs to the TACO1 family. TACO1 is a mitochondrial protein which functions as a translational activator of mitochondrially-encoded cytochrome c oxidase 1. Mutations in this gene are associated with Leigh syndrome.

GSTT2 belongs to the glutathione s-transferase (GST) family of proteins. There are eight GST proteins families, named alpha, kappa, mu, omega, pi, sigma, theta and zeta. Each one of the GST families has several proteins with different functions throughout the cell. The theta type members GSTT1 and GSTT2 have a 55% aa sequence homology and hold a vital role in human carcinogenesis. The theta genes are structurally similar – each has five exons with identical exon/intron boundaries.

PRSS3 is a trypsinogen, and a member of the trypsin family of serine proteases. PRSS3 is expressed in the pancreas and brain and is unaffected by common trypsin inhibitors. It is active on peptide linkages involving the carboxyl group of lysine or arginine. PRSS3 is restricted to the locus of T cell receptor beta variable orphans on chromosome 9. 4 different isoforms encoded by 4 transcript variants were identified for this gene.

NME2 takes an important part in the synthesis of nucleoside triphosphates other than ATP. NME2 negatively controls Rho activity by interacting with AKAP13/LBC. NME2 acts as a transcriptional activator of the MYC gene. NME2 binds DNA non-specifically. NME2 is a heterodimeric enzyme functioning as a nucleoside diphosphate kinase. NME1 and NME2 contain 152 amino acids, A and B polypeptide chains of the NM23 enzyme, respectively. NME2 is identical to the beta subunit of human erythrocyte NDP kinase. NDP kinases participate in the synthesis of nucleoside triphosphates, and NM23 is involved in the regulation of signal transduction by complexing with G proteins, causing activation/inactivation of developmental pathways.

IMP2 Inner Mitochondrial Membrane Peptidase-Like (IMMP2L) is implicated in processing the signal peptide sequences, IMMP2L is used to direct mitochondrial proteins to the mitochondria. IMMP2L resides in the mitochondria and is one of the essential proteins for the catalytic activity of the mitochondrial inner membrane peptidase (IMP) complex. Two variants which encode the same protein have been found for IMMP2L.

FtsJ RNA Methyltransferase Homolog 2 (FTSJ2) belongs to the S-adenosylmethionine-binding protein family. FTSJ2 is a nucleolar protein and which is involved in cell cycle control and DNA repair and the processing and modification of rRNA. FTSJ2 is extensively expressed, with the highest expression in the muscle, placenta, and heart.

Lysine Methyltransferase 5A (KMT5A) is an enzyme which catalyzes both histones and non-histone proteins. KMT5A contributes to the maintenance of proper higher-order structure of DNA during mitosis. KMT5A takes part in cell-cycle-dependent transcriptional silencing and mitotic regulation in metazoans. KMT5A plays a role as a barrier to prevent cellular senescence through chromatinmediated regulation of senescence-associated metabolic remodeling. KMT5A mediates monomethylation of p53/TP53 at 'Lys-382', which leads to repress p53/TP53-target genes. The loss of KMT5A simultaneously stimulate nucleolar function and retinoblastoma protein-mediated mitochondrial metabolism.

MSRB2 is a member of the methionine sulfoxide reductases(MSRs) family which are antioxidant repair enzymes. MSRB2 protein catalyzes the decrease of free and protein-bound methionine sulfoxide to methionine. MSRB2 has a part in protecting against oxidative stress in numerous organs.

Heparanase is an endo β-D-glucuronidase, which degrades heparan sulfate side chains of heparan sulfate proteoglycans (HSPGs) in the extracellular matrix. Heparanase plays an important role in ECM degradation, facilitating the migration and extravasation of tumor cells and inflammatory leukocytes (1,2,3). Upon degradation, heparanase releases growth factors and cytokines that stimulate cell proliferation and chemotaxis (4,5). Heparanase is a heterodimer comprised of a 50 kDa subunit harboring the active site and a 8 kDa subunit. It is produced as a latent 65 kDa precursor and proteolytically processed to its active form (1,6). Heparanase is highly expressed in myeloid leukocytes (i.e. neutrophils) in platelets and in human placenta. Human heparanase was found to be upregulated in various types of primary tumors, correlating in some cases with increased tumor invasiveness and vascularity and with poor prospective survival (7,8).

Prostaglandin Reductase 2 (PTGR2) is a member of the medium-chain dehydrogenase/reductase superfamily. PTGR2 is an enzyme involved in the metabolism of prostaglandins. PTGR2 catalyzes an NADPH-dependent reduction of the conjugated alpha, beta-unsaturated double bond of 15-keto-PGE(2), which is a fundamental step in terminal inactivation of prostaglandins and suppression of PPARgamma-mediated adipocyte differentiation. PTGR2 may also be involved in controlling activation of the peroxisome proliferator-activated receptor.

Cathepsin F ( CTSF) is a member of the peptidase C1 family. Cathepsins are papain familycysteine proteinases which are a main component of the lysosomal proteolytic system. The CTSF gene isubiquitously expressed, and it maps to chromosome 11q13, close to the gene encoding cathepsin W. CTSF plays a role in normal protein catabolism. CTSF involved in some degradative processes occurring in tumor progression since it is highly expressed in some cancer cell lines.

TIMP2 belongs to the TIMP gene family. The proteins encoded by this gene family are natural inhibitors of the matrix metalloproteinases, a group of peptidases that take part in degradation of the extracellular matrix. Besides having an inhibitory role against metalloproteinases, the encoded protein has a exclusive part among TIMPfamily members in its capability to directly suppress the proliferation of endothelial cells. Consequently, the encoded protein is crucial to the conservation of tissue homeostasis by suppressing the production of quiescent tissues as an answer to angiogenic factors, and by inhibiting protease activity in tissues undergoing renovation of the extracellular matrix.

P450 Oxidoreductase, also known as POR is a flavoprotein which contributes electrons to all microsomal P450 enzymes. POR is localized to the endoplasmic reticulum, where it is also capable of transfering electrons to heme oxygenase as well as cytochrome b5. POR is structurally related to two separate flavoprotein families; first one is ferredoxin nucleotide reductase and the second flavodoxin.

PSMA1 is a prosomal protein who takes part in a nonlysosomal ATP/ubiquitin-dependent proteolytic pathway. PSMA1 is a multicatalytic proteinase complex that is characterized by its capacity to cleave peptides with Arg, Phe, Tyr, Leu, and Glu next to the leaving group at neutral or slightly basic pH. PSMA1 is vastly expressed in prostate epithelium.

Beta-galactosidase is a hydrolase enzyme that catalyzes the hydrolysis of Beta-galactosides into monosaccharides. Substrates of different Beta-galactosidases include ganglioside GM1, lactosylceramides, lactose, and various glycoproteins. Beta-galactosidase is produced In E. coli by activation of the lac operon as the lacZ gene.