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Protein modification with ubiquitin is an essential cellular mechanism for targeting abnormal or short-lived proteins for degradation. Ubiquitination involves at least 3 classes of enzymes: ubiquitin-activating enzymes (E1s) ubiquitin-conjugating enzymes (E2s) and ubiquitin-protein ligases (E3s). Ubiquitin-Conjugating Enzyme E2G (UBE2G1) belongs to the E2 ubiquitin-conjugating enzyme family and catalyzes the covalent attachment of ubiquitin to other proteins. UE2G1 protein is involved in degradation of muscle-specific proteins.

HPRT1 has a main part in the generation of purine nucleotides through the purine salvage pathway. HPRT1 primarily functions to salvage purines from degraded DNA to renewed purine synthesis. Therefore, it performs as a catalyst in the reaction between guanine and phosphoribosyl pyrophosphate to form GMP.

Human immunodeficiency virus type-1 (HIV-1) regulatory Tat protein plays an essential role in viral replication (Jones KA, 1994) and infectivity (Arya SK, 1985; Fisher AG, 1986). In addition, during acute infection, Tat is released extracellularly by infected cells (Chang HC, 1997; Ensoli B, 1990) and is taken up by neighboring cells where it transactivates viral replication (Ensoli B, 1993) and increases virus infectivity.
HIV-1 Tat activates transcription of HIV-1 viral genes by inducing phosphorylation of the C-terminal domain (CTD) of RNA polymerase II (RNAPII). Tat can also disturb cellular metabolism by inhibiting proliferation of antigen-specific T lymphocytes and by inducing cellular apoptosis. Tat-induced apoptosis of T-cells is attributed, in part, to the distortion of microtubules polymerization. LIS1 is a microtubule-associated protein that facilitates microtubule polymerization.

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.

PSMA6 belongs to the peptidase T1A family, which is a 20S core alpha subunit. The proteasome is a multicatalytic proteinase complex with an extremely organized ring-shaped 20S core structure. The core structure consists of 4 rings of 28 non-identical subunits; 2 rings consist of 7 alpha subunits and 2 rings consist of 7 beta subunits. PSMA6 is spread all over eukaryotic cells in large quantities and cleave peptides in an ATP/ubiquitin-dependent procedure in a non-lysosomal pathway.

PRDX2 is part of the peroxiredoxin family of antioxidant enzymes, which reduce hydrogen peroxide and alkyl hydroperoxides. PRDX2 takes part as an antioxidant protective role in cells, and contributes to the antiviral activity of CD8(+) T-cells. PRDX2 has proliferative effect in cancer development or progression.
If PRDX2 protection is insufficient against peroxidases, the DNA damage results in neurological disease such as Alzheimer's or DNA damage leading to cancer.

Phosphomannomutase 1 (PMM1) is an enzyme involved in the synthesis of the GDP-mannose and dolichol-phosphate-mannose required for a number of critical mannosyl transfer reactions. PMM1 catalyzes the conversion between D-mannose 6-phosphate and D-mannose 1-phosphate which is a substrate for GDP-mannose synthesis. GDP-mannose is used for the synthesis of dolichol-phosphate-mannose, which is crucial for N-linked glycosylation and accordingly the secretion of several glycoproteins as well as for the synthesis of glycosyl-phosphatidyl-inositol (GPI) anchored proteins. Additionally, PMM1 may be responsible for the degradation of glucose-1,6-bisphosphate in ischemic brain.

Human immunodeficiency virus type-1 (HIV-1) regulatory Tat protein plays an essential role in viral replication and infectivity. In addition, during acute infection, Tat is released extracellularly by infected cells and is taken up by neighboring cells where it transactivates viral replication and increases virus infectivity.
HIV-1 Tat activates transcription of HIV-1 viral genes by inducing phosphorylation of the C-terminal domain (CTD) of RNA polymerase II (RNAPII). Tat can also disturb cellular metabolism by inhibiting proliferation of antigen-specific T lymphocytes and by inducing cellular apoptosis. Tat-induced apoptosis of T-cells is attributed, in part, to the distortion of microtubules polymerization. LIS1 is a microtubule-associated protein that facilitates microtubule polymerization.

Mps one binder kinase activator-like 3 (MOBKL3) is a member of the MOB1/Phocein family and is phosphorylated on serine residues. MOBKL3 is usually linked with membranes but can be present in the cytosol, where it behaves as a protein complex. MOBKL3 is the major partner of the striatin family members, which are scaffolding proteins involved in signaling and trafficking.

PCK1 is a central regulating point for the regulation of gluconeogenesis. PCK1 has a vital part in this process by stimulating hepatic glucose production. The expression of PCK1 is controlled by cAMP, glucocorticoids, diet etc. Modulation of the signals controlling PCK1 levels offers a possible therapeutic tactic to the treatment of Diabetes and subsequently obesity.

Uromodulin is the most abundant protein in normal urine. Its secretion in urine follows proteolytic cleavage of the ectodomain of its glycosyl phosphatidylinosital-anchored counterpart that is situated on the luminal cell surface of the loop of Henle. Uromodulin plays a role as a constitutive inhibitor of calcium crystallization in renal fluids. Secretion of uromodulin in urine provides protection against urinary tract infections caused by uropathogenic bacteria. Defects in Uromodulin expression are associated with the autosomal dominant renal disorders medullary cystic kidney disease-2 (MCKD2) and familial juvenile hyperuricemic nephropathy (FJHN). These disorders are characterized by juvenile onset of hyperuricemia, gout, and progressive renal failure. While several transcript variants may exist for this gene, the full-length natures of only two have been described to date. UMOD is involved in regulating the circulating activity of cytokines as it binds to il-1, il-2 and tnf with high affinity.

CTDSP1 is a class 2C phosphatase with activity dependent on the conserved DxD motif. CTDSP1 preferentially catalyzes the dephosphorylation of 'Ser-5' within the tandem 7 residues repeats in the C-terminal domain (CTD) of the largest RNA polymerase II subunit POLR2A. In addition, CTDSP1 negatively regulates RNA polymerase II transcription, possibly by controlling the transition from initiation/capping to processive transcript elongation.

Coagulation factor VII is a vitamin K-dependent factor which is essential for hemostasis. It circulates in the blood as a zymogen which is later converted to an active form by factor IXa, factor Xa, factor XIIa, or thrombin by minor proteolysis. Upon activation of factor VII, a heavy chain with a catalytic domain and a light chain with 2 EGF-like domains are generated, and the two chains are held together by a disulfide bond. The presence of factor III and calcium ions further activates the coagulation cascade by converting factor IX to factor IXa and/or factor X to factor Xa. Alternative splicing of factor VII results in 2 transcripts. Defects in coagulation factor VII can cause coagulopathy. Coagulation factor VII initiates the extrinsic pathway of blood coagulation. Minor proteolysis converts factor VII to factor VIIa by factors Xa, XIIa, IXa, or thrombin. Factor VIIa also converts factor IX to factor IXa in the presence of tissue factor and calcium.

Frizzled-4, also known as FZD4 is a 7 ­transmembrane glycoprotein which belongs to the Frizzled family within the G-protein coupled receptor superfamily. FZD4 acts as a positive regulator of the Wingless type MMTV integration site signaling pathway. These pathways appear to include interactions with G-proteins. FZD4 is implicated in transduction as well as intercellular transmission of polarity information in the course of tissue morphogenesis and differentiated tissues.

Ribosomal Protein L35, also known as RPL35 is a ribosomal protein which is a component of the 60S subunit. Ribosomes are the organelles which catalyze protein synthesis, they consist of a small 40S subunit and a large 60S subunit. Jointly these subunits are composed of 4 RNA species and about 80 structurally different proteins. RPL35 is a member of the L29P family of ribosomal proteins. RPL35 is located in the cytoplasm. As typicaly for genes encoding ribosomal proteins, there are multiple processed pseudogenes of RPL35 dispersed through the genome.

Osteopontin is a glycoprotein that was first identified in osteoblasts and is involved in bone remodeling, immune functions in fibroblasts, macrophages, and lymphocytes during inflammation and wound healing. SPP1 binds tightly to hydroxyapatite. SPP1 forms an integral part of the mineralized matrix. SPP1 is vital to cell-matrix interaction. Secreted Phosphoprotein-1 protects against cardiac ischemia-reperfusion injury via late preconditioning. Expression of both Ostepontin and CD44 in hepatocellular carcinoma is linked with advanced tumor stage and contributes to prognosis information. SPP1 is the most over-expressed gene in intrahepatic cholangiocarcinoma. Secreted Phosphoprotein-1 overexpression is related with interstitial lung diseases.

DUSPs are distinguished by their ability to dephosphorylate both tyrosine and serine/threonine residues. DUSPs have been implicated as major modulators of critical signaling pathways. Dual specificity phosphatase 19 (DUSP19) belongs to the dual specificity protein phosphatase subfamily. DUSP19 is a protein phosphatase which functions as a stress-activated protein kinase pathway-regulating phosphatase. DUSP19 contains a variation of the consensus DUSP C-terminal catalytic domain, with the last serine residue replaced by alanine, and lacks the N-terminal CH2 domain found in the MKP class of DUSPs.

Thrombopoietin is a glycoprotein hormone produced mainly by the liver and the kidney which regulates the production of platelets by the bone marrow. TPO stimulates the production as well as differentiation of megakaryocytes, the bone marrow cells which fragment into large numbers of platelets.

Protein phosphatase 1 regulatory subunit 11 (PPP1R11) is located within the major histocompatibility complex class I region on chromosome 6 and is expressed in a variety of both adult and embryonic tissues. PPP1R11 acts as an inhibitor of PP1 (protein phosphatase 1), particularly showing a sensitivity toward the metal-independent and metal-dependent forms of PP1. Deletion of a portion of the q arm of chromosome 6 is related with early onset intestinal cancer, proposing the presence of a cancer vulnerability locus.

Protein Phosphatase 1, Regulatory Subunit 8 (PPP1R8) is the RNA-binding subunit of a key species of protein phosphatase-1 in the nucleus. The PPP1R8 enzyme is an inhibitor subunit of the main nuclear protein phosphatase-1 (PP-1). PPP1R8 has RNA-binding activity however it doesn’t cleave RNA and may target PP-1 to RNA-associated substrates. Two isoforms of the PPP1R8 protein are specific inhibitors of type 1 serine/threonine protein phosphatases which can bind but not cleave RNA. The third isoform of the PPP1R8 protein is deficient in of the phosphatase inhibitory activity nonetheless it is a single-strand endoribonuclease comparable to RNase E of E. coli.

VPS29 is a member of a group of genes coding for vacuolar protein sorting (VPS) proteins which, when functionally damaged, lessens the efficient transfer of vacuolar hydrolases. VPS29 is a late Golgi transmembrane protein that operates as the sorting receptor for soluble vacuolar hydrolases, from the prevacuolar endosome back to the Golgi. Moreover, VPS29 takes part in the creation of the inner shell of the retromer coat for retrograde vesicles parting the prevacuolar compartment.

Ectonucleoside Triphosphate Diphosphohydrolase 6 or ENTPD6 is an enzyme, akin to E-type nucleotidases. E-type nucleotidases, for instance CD39, are responsible for extracellular nucleotides catabolism. ENTPD6 has four apyrase-conserved areas like all to E-type nucleotidases. Rather spliced transcript agents that codes various isoforms were discovered for the DNA segment.

PEA15 (Phospho-enriched protein in astrocytes 15kDa) is a death effector domain (DED)-containing protein mainly expressed in the central nervous system, principally in astrocytes. PEA15 is implicated in the regulation of various cellular processes including apoptosis, proliferation, glucose transport, adhesion and migration. Increased PEA15 levels have an affect tumorigenesis and cancer progression, therefore it is overexpressed in breast cancers and gliomas as well as in type 2 diabetes. PEA15 blocks Ras-mediated inhibition of integrin activation and modulates the ERK MAP kinase cascade. PEA15 also inhibits RPS6KA3 activities by holding it in the cytoplasm. In addition, PEA15 inhibits both TNFRSF6 and TNFRSF1A mediated CASP8 activity and apoptosis.
PEA15 is ubiquitously expressed. PEA15 is most abundant in tissues such as the heart, brain, muscle and adipose tissue which use glucose as an energy source. Lower PEA15 expression is in glucose-producing tissues. Higher levels of PEA15 expression are found in tissues from individuals with type 2 diabetes than in controls.
PEA15 expression is a significant prognostic marker in ovarian cancer.

Phosphoglycerate mutase 2 (PGAM2) is a member of the phosphoglycerate mutase family. PGAM is a dimeric enzyme which contains in separate tissues, different proportions of a slow-migrating muscle (MM) isozyme, a fast-migrating brain (BB) isozyme, and a hybrid form (MB). PGAM (Phosphoglycerate mutase) catalyzes the reversible reaction of 3-phosphoglycerate (3-PGA) to 2-phosphoglycerate (2-PGA) in the glycolytic pathway. PGAM2 gene mutations cause muscle phosphoglycerate mutase efficiency, otherwise known as glycogen storage disease X.