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DPP4 also called adenosine deaminase complexing protein-2, and T-cell activation antigen CD26 is a serine exopeptidase and complex enzyme that is expressed on the surface of most cell types. DPPIV is an intrinsic membrane glycoprotein and a serine exopeptidase that cleaves X-proline dipeptides from the N-terminus of polypeptides. DPP4 plays a role in t-cell activation. DPP4 is associated with intracellular signal transduction, apoptosis and involved in tumor biology. There are at least 63 substrates which can bind specifically to DPP4 enzyme including growth factors, chemokines, neuro peptides. Furthermore, DPP4 plays a major role in glucose metabolism by cleaving incretins such as glucose-dependent insulinotropic polypeptide (GIP) and GLP-1.

Matrix metalloproteinase-2 (MMP-2) is involved in endometrial menstrual breakdown, regulation of vascularization and the inflammatory response. MMP-2 contains a number of distinct domains: a prodomain that is cleaved upon activation; a catalytic domain containing the zinc binding site; a fibronectin like domain believed to have a role in substrate targeting; and a carboxyl terminal (hemopexin like) domain containing 2 N-linked glycosylation. The MMP-2 can degrade an extensive array of substrates including type IV, V, VII and X collagens as well as gelatin type I. In addition, MMP-2 interacts with THBS2, TIMP2, Thrombospondin 1, CCL7 and TIMP4. MMP-2 autocatalytic cleavage in the C-terminal generates the anti-angiogenic peptide, PEX. This process seems to be made possible by binding integrinv/beta3. Defects in the MMP-2 are the cause of Torg-Winchester syndrome (TWS), aka multicentric osteolysis nodulosis and arthropathy (MONA).

Lymphokine-activated killer T-cell-originated protein kinase (PBK) is a serine/threonine kinase related to the dual specific mitogen-activated protein kinase (MAPKK) family. PBK is abundant in placenta (is also found in the testis’ outer cell layer of seminiferous tubules) and absent from adult brain tissue. PBK is involved in the activation of lymphoid cells and supports testicular functions, with a possible role in the process of spermatogenesis. Mitotic phosphorylation is required for PBK’s catalytic activity. Once phosphorylated,PBK forms a complex with TP53, leading to TP53 destabilization and weakening of G2/M checkpoint during some kind of DNA damage. PBK is active only during mitosis. In addition, a PDZ domain in the tumor suppressor protein Dlg can coordinate with the T/SXV motif of PBK. PBK also phosphorylates MAP kinase p38, and may have a role in the activation of lymphoid cells.

Celiac disease is an enteropathy that is characterized by intestinal lesions of variable severity. Tissue-type transglutaminase (tTG) is believed to be the predominant autoantigen for celiac disease and the corresponding autoantibodies show higher sensitivity and specificity than anti-gliadin antibodies. Highly pure recombinant human tTG is now available to replace the traditionally used tTG fraction from guinea pig.
Tissue-type transglutaminase antigens have been specifically modified for improved handling: exchange of an active site amino acid eliminates the protein cross-linking activity of the enzyme, while maintaining the native three-dimensional structure and the enzyme's secondary GTPase activity. This engineering assures reproducible properties of the antigen preparations through the absence of variable and ill-defined covalent aggregates of tTG antigen and host cell proteins.

Aspartic Peptidase, Retroviral-Like 1 (ASPRV1) is a protein which contains one peptidase A2 domain. ASPRV1 undergoes autocleavage which is essential for activation of the protein. ASPRV1 is expressed mostly in the granular layer of the epidermis and inner root sheath of hair follicles and localized to membrane region. In the psoriatic skin, ASPRV1 is expressed throughout the stratum corneum. In the ulcerated skin, ASPRV1 is expressed in the stratum granulosum of intact epidermis; however it is virtually nonexistent from ulcerated regions. In addition, ASPRV1 is expressed in differentiated areas of squamous cell carcinomas but not in the undifferentiated tumors.

Myeloid/Lymphoid Leukemia Translocated To 11 (MLLT11) is a part of the Mixed-Lineage Leukemia protein family. MLLT11 which takes part in leukemogenesis and in the progression of severe monocytic leukemia (AML) is located on chromosome 11q23. MLLT11 which is also expressed in embryonic brain cortex is upregulated during neuronal differentiation and is taking part in the evolution of the central nervous system.

LASP1 has a vital part in the regulation of dynamic actin-based, cytoskeletal activities. Agonist-dependent changes in LASP1 phosphorylation can additionally assist in regulation of actin-associated ion transport activities in the parietal cell and in several other F-actin-rich secretory epithelial cell types.

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.

IFIH1 is a DEAD box protein which is upregulated in response to treatment with beta-interferon and a protein kinase C-activating compound, mezerein. Irreversible reprogramming of melanomas can be attained by therapy with both these agents; treatment with either agent alone only achieves reversible differentiation. DEAD box proteins are implicated in several cellular processes involving alteration of RNA secondary structure such as translation initiation, nuclear and mitochondrial splicing, and ribosome and spliceosome assembly.

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.

PDIA3 is an enzyme that belongs to the endoplasmic reticulum and interacts with lectin chaperones calreticulin and calnexin to modulate folding of newly synthesized glycoproteins. PDIA3 has protein disulfide isomerase activity. Complexes of lectins and PDIA3 mediate protein folding by promoting formation of disulfide bonds in their glycoprotein substrates. PDIA3 is expressed in the lumbar spinal cord from rats submitted to peripheral lesion during neonatal period. PDIA3 interacts with thiazide-sensitive sodium-chloride cotransporter in the kidney and is induced by glucose deprivation. PDIA3 is part of the major histocompatibility complex (MHC) class I peptide-loading complex (TAP1), which is important for formation of the final antigen conformation and export from the endoplasmic reticulum to the cell surface.

The Proteinase K enzyme is a member of the Peptidase family S8. Proteinase K is a broad-spectrum serine protease. Proteinase K is capable of digesting hair (keratin), henceforth, the name "Proteinase K". Proteinase K is activated by calcium, the enzyme digests proteins especially after hydrophobic amino acids (aliphatic, aromatic and other hydrophobic amino acids). Proteinase K is frequently utilized in molecular biology to digest protein and remove contamination from preparations of nucleic acid. Addition of Proteinase K to nucleic acid preparations rapidly inactivates nucleases which may otherwise degrade the DNA or RNA during purification. Proteinase K is greatly fitting to this application as the enzyme is active in the presence of chemicals which denature proteins, such as SDS and urea, chelating agents such as EDTA, sulfhydryl reagents, as well as trypsin or chymotrypsin inhibitors. Proteinase K is utilized for the destruction of proteins in cell lysates (tissue, cell culture cells) and for the release of nucleic acids, given that it quite effectively inactivates DNases and RNases.

PDCD6IP is a Class E VPS protein which participates in concentration and sorting of cargo proteins of the multivesicular body or incorporation into intralumenal vesicles that are generated by invagination and scission from the limiting membrane of the endosome. PDCD6IP binds to the phospholipid lysobisphosphatidic acid which is abundant in MVBs internal membranes. The MVB pathway appears to require the sequential function of ESCRT-O, -I,-II and -III complexes. PDCD6IP is an adapter for a subset of ESCRT-III proteins, such as CHMP4, to function at distinct membranes. PDCD6IP is mandatory for completion of cytokinesis. PDCD6IP takes part in HIV-1 virus budding. PDCD6IP replaces TSG101 in its function of supporting HIV-1 release. PDCD6IP takes part in the regulation of both apoptosis and cell proliferation. PDCD6IP is a cytoplasmic protein that cooperates with apoptosis-associated proteins (ALG-2 and PDCD6) and with the endocytosis-regulator CIN85. Overexpression of PDCD6IP and endophilin

PDK1 takes part in the regulation of enzymatic activity of mammalian pyruvate dehydrogenase which is part of a mitochondrial multienzyme complex to catalyze the oxidative decarboxylation of pyruvate and is one of the major enzymes responsible for the regulation of homeostasis of carbohydrate fuels in mammals. PDK1 inhibits glioblastoma growth. PDK1 inhibits the mitochondrial pyruvate dehydrogenase complex by phosphorylation of the e1 alpha subunit, therefore contributing to the regulation of glucose metabolism. PDK1 kinase activity is negatively regulated by binding to 14-3-3.

E3 ubiquitin-protein ligase SIAH1 (SIAH1) belongs to the SIAH (seven in absentia homolog) family. SIAH1 is a tumor suppressor protein, which is expressed in intestinal epithelium and activated during apoptosis. SIAH1 is involved in ubiquitination and proteasome-mediated degradation of specific proteins. SIAH1 is comprised of an N-terminal RING-finger domain (required for proteolysis) and a cystein-rich C-terminal domain (which regulates oligomerization and SIAH binding to target proteins). SIAH1 causes indirect degradation of beta-catenin by way of creation of a complex with Siah-interacting protein (SIP), Skp1 and Ebi.

Kallikrein-3 (KLK3) is a part of the kallikrein-related peptidase family. Kallikreins are a subgroup of serine proteases having various physiological functions. Numerous kallikreins take part in carcinogenesis and some may be prospective cancer and other disease biomarkers. Kallikrein-3 is 1 of the 15 kallikrein subfamily members located in a cluster on chromosome 19 and is a protease present in seminal plasma. KLK3 hydrolyzes semenogelin-1 consequently leading to the liquefaction of the seminal coagulum. KLK3 acts normally in the liquefaction of seminal coagulum, probably by hydrolysis of the high molecular mass seminal vesicle protein. Serum level of the KLK3 protein, called PSA in the clinical setting, is beneficial in the diagnosis and monitoring of prostatic carcinoma.

Ribulose-phosphate 3-epimerase (RPE) is a member of the ribulose-phosphate 3-epimerase family. RPE is the enzyme which converts D-ribulose 5-phosphate into D-xylulose 5-phosphate in Calvin's reductive pentose phosphate cycle. Therefore, the RPE enzyme has one substrate, D-ribulose 5-phosphate, and one product, D-xylulose 5-phosphate. RPE participates in three metabolic pathways: pentose phosphate pathway, pentose and glucuronate interconversions, and carbon fixation.

6-PyruvoylTetrahydropterin Synthase is part of the family of lyases, specifically those carbon-oxygen lyases acting on phosphates. 6-PyruvoylTetrahydropterin Synthase catalyzes the elimination of inorganic triphosphate from dihydroneopterin triphosphate, which is the second and irreversible step in the biosynthesis of tetrahydrobiopterin from GTP. Tetrahydrobiopterin, is a necessary cofactor and regulator of a range of enzyme activities, including enzymes involved in serotonin biosynthesis and NO synthase activity. Mutations in 6-PyruvoylTetrahydropterin Synthase gene result in hyperphenylalaninemia.

FKBP14 enzyme accelerates the folding of proteins during protein synthesis. FKBP14 contains 2 EF-hand domains and one PPIase FKBP-type domain. Truncation of the amino-terminus of FKBP14 significantly decreases peptidyl prolyl cis-trans isomerase activity, therefore implicating that the PPIase FKBP-type domain must be located at the N-terminus.

PGAM1 is part of the phosphoglycerate mutase family. PGAM1 is an essential component of glucose and 2,3-BPGA (2,3-bisphosphoglycerate) metabolism and catalyzes the reversible reaction of 3-phosphoglycerate (3-PGA) to 2-phosphoglycerate (2-PGA) in the glycolytic pathway. PGAM1 is a dimeric enzyme containing, in different tissues, different proportions of a slow-migrating muscle (MM) isozyme, a fast-migrating brain (BB) isozyme, and a hybrid form (MB). PGAM1 mutations lead to muscle phosphoglycerate mutase deficiency, a.k.a. glycogen storage disease X.

POU5F1 is a homeodomain transcription factor of the POU family, expressed in embryonic stem (ES) cells and embryonic carcinoma (EC) cells.POU5F1 is significantly involved in the signaling pathway for maintaining self-renewal and pluripotency of ES cells. POU5F1 has 2 distinct DNA binding domains which independently bind half-sites of the canonical octamer motif. This flexibility allows POU5F1 to bind with distinct DNA motifs by forming heterodimers with other transcription factors or by forming homodimers in several conformations. Human POU5F1 contains a 75aa POU specific (POUS) domain and a 60aa POU-Homeo-(POUH) domain connected by a linker region. The Human POU5F1 specifically interacts with Octamer motif ATGCAAAT. In addition, 2 proline-rich domains in the N-terminal and C-terminal regions are vital for POU5F1 transactivation. POU5F1 regulates a number of target genes and has been shown to work jointly with other transcription factors including Sox2 as well as Nanog to sustain stem cell potency and self-renewal.

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.

KISS1 is a metastasis suppressor protein that suppresses metastases of melanomas and breast carcinomas without affecting tumorigenicity.KISS1 functions to inhibit chemotaxis and invasion, attenuating metastasis in malignant melanomas. KISS1 is involved in the regulation of cell-matrix adhesion. KISS1 plays a role in cytoskeletal reorganization. A polymorphism in the terminal exon of KISS1 mRNA results in two protein isoforms. Expression of KiSS1 is localized to specific regions of the hypothalamus in numerous species and is regulated by gonadal steroids and across the estrous cycle..KISS1 generates a c-terminally amidated peptide, metastin which functions as the endogenous ligand of the g-protein coupled receptor gpr54. Activation of the receptor inhibits cell proliferation and cell migration, key characteristics of tumor metastasis.

GIPC1 is a PDZ domain protein that cooperates with RGS-GAIP and the viral oncoprotein TAX, which transactivates viral and cellular promoters throughout interactions with different transcription factors. GIPC1 particularly localizes to clusters of vesicles close to the plasma membrane and takes part in G protein-coupled signaling pathway participating in regulating Clathrin-coated vesicular trafficking. GIPC1 cooperates with membrane bound Semaphorin F, which is takes part in neuronal axon growth, and controls the subcellular distribution of M-SemF in the brain.