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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.

FARSB, also known as Phenylalanyl-TRNA Synthetase Beta is a member of the phenylalanyl-tRNA synthetase beta subunit family. FARSB is composed tetramer of two alpha and two beta subunits. In the presence of ATP, this tetramer is accountable for attaching L-phenylalanine to the terminal adenosine of the appropriate tRNA.

Ubiquitin-Conjugating Enzyme E2G2 (UBE2G2) is a protein coding gene which is a part of the E2 ubiquitin-conjugating enzyme family. UBE2G2 accepts ubiquitin from the E1 complex and catalyzes its covalent attachment to various proteins. UBE2G2 is ubiquitously expressed mainly in adult muscle. UBE2G2 also takes part in endoplasmic reticulum-associated degradation (ERAD).

UBE2T is part of the E2 ubiquitin-conjugating enzyme family that participates in the protein degradation pathway. UBE2T catalyzes the ATP-dependent attachment of ubiquitin to target proteins, thus tagging them for subsequent destruction by the proteasome. UBE2T is an important factor of the Faconi anemia pathway of DNA damage repair and, upon self-inactivation, may negatively regulate the Faconi pathway.

Threonyl-tRNA Synthetase is a member of the aminoacyl-tRNA synthetase family, key enzymes of protein biosynthesis which charge tRNA molecules with the respective amino acids. This 83 kDa protein is an autoantigen recognized by PL-7 antibodies which occur in a subset of patients with polymyositis and dermatomyositis. Preliminary data suggest that PL-7 antibodies (similar to Jo-1 antibodies) indicate an increased risk for lung involvement, but this needs to be confirmed for a larger number of cases.

Ubiquitin-conjugating enzyme E2 R2 (UBE2R2) is a member of the ubiquitin-conjugating enzyme family. Protein kinase CK2 is a ubiquitous and pleiotropic Ser/Thr protein kinase implicated in cell growth andtransformation. This protein is a protein similar to the E2 ubiquitin conjugating enzyme UBC3/CDC34. Studies propose that CK2-dependent phosphorylation of this ubiquitin-conjugating enzyme functions by regulating beta-TrCP substrate recognition and induces its interaction with beta-TrCP, enhancing beta-catenin degradation. UBE2R2 receives ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins. In vitro catalyzes monoubiquitination and 'Lys-48'-linked polyubiquitination. UBE2R2 may be implicated in degradation of katenin. Among the diseases associated with UBE2R2 are cblc, and herpes simplex.

MTHFS is a cytosolic protein which takes part in the formate metabolic process. MTHFS along with a magnesium cofactor catalyzes the ATP-dependent reaction which reduces 5-formyltetrahydrofolate (5-MTHF) to 5,10-methenyltetrahydrofolate(MTHF). MTHF is the substrate used by MTHFR (methylenetetrahydrofolate reductase) to generate 5-MTHF. In addition, MTHF is a coenzyme used in thymidine biosynthesis by thymidylate synthase (FAD).

L-threonine to glycine degradation consists of a two-step biochemical pathway which involvs the enzymes L-threonine dehydrogenase and 2-amino-3-ketobutyrate coenzyme A ligase. L-Threonine is initially converted into 2-amino-3-ketobutyrate by L-threonine dehydrogenase. Glycine C-Acetyltransferase (GCAT) is the 2nd enzyme in this pathway, which subsequently catalyzes the reaction between 2-amino-3-ketobutyrate and coenzyme A to form glycine and acetyl-CoA. The GCAT enzyme is regard as a class II pyridoxal-phosphate-dependent aminotransferase. GCAT is strongly expressed in the heart, brain, liver and pancreas. GCAT is also found in lung.

Pellino E3 Ubiquitin Protein Ligase Family Member 2, also known as PELI2 is an E3 ubiquitin ligase which catalyzes the covalent attachment of ubiquitin moieties onto substrate proteins. PELI2 is implicated in the TLR and IL-1 signaling pathways through interaction with the complex which contain IRAK kinases and TRAF6. PELI2 also mediates IL1B-induced IRAK1 'Lys-63'-linked polyubiquitination and possibly 'Lys-48'-linked ubiquitination. PELI2 is significant for LPS- and IL1B-induced MAP3K7-dependent, however not for MAP3K3-dependent, NF-kappa-B activation. Moreover, PELI2 can activate the MAP (mitogen activated protein) kinase pathway directing to activation of ELK1.

Ring Finger Protein 114 (RNF114) is expressed in various tissues, including skin, CD4 lymphocytes and dendritic cells. RNF114, which contains 1 RING-type zinc finger, takes part in spermatogenesis.

Ubiquitin Conjugating Enzyme E2Q2 (UBE2Q2) is a protein coding gene which receives ubiquitin from the E1 complex and catalyzes its covalent attachment to various proteins. UBE2Q2 which is a part of the ubiquitin-conjugating enzyme family is detected in hypopharyngeal head and neck squamous cell carcinoma and in tumor masses.

Threonyl-tRNA synthetase, cytoplasmic (TARS) is a member of the class-II aminoacyl-tRNA synthetase family. The main role of TARS is in tRNA aminoacylation. The N-terminal domain of the TARS enzyme is responsible for the competition with the ribosome whereas the catalytic and the C-terminal domain are involved in binding the 2 anticodon arm-like structures in the operator.

UBE2D2 belongs to the E2 ubiquitin-conjugating enzyme family. UBE2D2 takes part in the ubiquitination of the tumor-suppressor protein p53, which is induced by an E3 ubiquitin-protein ligase. UBE2D2 catalyzes ubiquitination of IkB-alpha in a SCFB-TRCP and phosphorylation dependent method.

Tripartite Motif Containing 33 (TRIM33) belongs to the tripartite motif family. This motif includes 3 zinc-binding domains, a RING, a B-box type 1 and a B-box type 2, and a coiled-coil region. TRIM33 is assumed to be a transcriptional corepressor. TRIM33 functions as an E3 ubiquitin-protein ligase. TRIM33 also promotes SMAD4 ubiquitination, nuclear exclusion and degradation via the ubiquitin proteasome pathway. In addition, TRIM33 inhibits the transcriptional response to TGF-beta/BMP signaling cascade. Furthermore, TRIM33 has a role in the control of cell proliferation.

Ubiquitin-conjugating enzyme E2 F (UBE2F) is a member of the ubiquitin-conjugating enzyme family and UBE2F subfamily. Ubiquitin-conjugating enzymes or sometimes as ubiquitin-carrier enzymes, run the second step in the ubiquitination reaction which targets a protein for degradation using the proteasome. The UBE2F receives the ubiquitin-like protein NEDD8 from the UBA3-NAE1 E1 complex and catalyzes its covalent attachment to other proteins.
RBX2-UBE2F complex neddylates specific target proteins, for example CUL5 as can be seen from the specific interaction with the E3 ubiquitin ligase RBX2, but not RBX1.

UbcH12 is functional in in vitro NEDDylation reactions. It has been shown to form a thioester linkage with NEDD8 in the presence of the NEDD8 activating enzyme complex Uba3/APP-BP1. APP-BP1 binds to the amyloid precursor protein (APP) carboxy terminal domain and is important in conjunction with Uba3 and UbcH12 in driving cells through the S to M checkpoint. It was demonstrated to be the E2 responsible for the NEDDylation of the Cul-1 component of the SCF (?-TRCP) complex which is important as the E3-ligase in the ubiquitinylation of I?B?. NEDDylation of Cul-1 is essential for conjugation and processing of NF-?B p105 by SCF (?-TRCP) following phosphorylation of the complex. A dominant negative form of UbcH12, previously demonstrated to sequester NEDD8 and inhibit its conjugation, inhibits both conjugation and processing of p105, which is alleviated by wild-type UbcH12.

Adenylosuccinate lyase (ADSL) is an enzyme which converts adenylosuccinate to AMP and fumarate as part of the purine nucleotide cycle. ADSL is involved in both de novo synthesis of purines and formation of adenosine monophosphate from inosine monophosphate. ADSL catalyzes 2 reactions in AMP biosynthesis: the removal of a fumarate from succinylaminoimidazole carboxamide (SAICA) ribotide to yield aminoimidazole carboxamide ribotide (AICA) and removal of fumarate from adenylosuccinate to yield AMP. Defects in the ADSL are the cause of adenylosuccinase deficiency (ADSL deficiency). ADSL deficiency is an autosomal recessive disorder distinguished by the accumulation in the body fluids of succinylaminoimidazole-carboxamide riboside (SAICA-riboside) and succinyladenosine (S-Ado). Adenylosuccinase deficiency results in succinylpurinemic autism, psychomotor retardation, and in some cases, growth retardation associated with muscle wasting and epilepsy.

WARS is part of the class I tRNA synthetase family. 2 types of tryptophanyl tRNA synthetase exist, a cytoplasmic form, called WARS, and a mitochondrial form, called WARS2. WARS catalyzes the aminoacylation of tRNA(trp) with tryptophan and is induced by INF. WARS controls ERK, Akt, and eNOS activation pathways that are related with angiogenesis, cytoskeletal reorganization and shear stress-responsive gene expression.

GLUL catalyzes the synthesis of glutamine from glutamate and ammonia. Glutamine is a major source of energy and that takes part in cell proliferation, inhibition of apoptosis, and cell signaling. GLUL is expressed during early fetal stages, and has a role in maintaining body pH by removing ammonia from circulation. Mutations in GLUL gene are related with congenital glutamine deficiency.

Acyl-CoA synthetase family member 2, also known as ACSF2 is a member of the ATP-dependent AMP-binding enzyme family. Acyl-CoA synthetases are a family of enzymes which catalyze the thioesterification of fatty acids with coenzymeA to form activated intermediates, which play a basic part in lipid metabolism as well as homeostasis of lipid-related processes. ACSF2 is required for the complex of lipid synthesis, energy production via beta-oxidation, protein acylation and fatty-acid dependent transcriptional regulation. Moreover, ACSF2 is required for fatty acid import into cells by the process of vectorial acylation.

Ubiquitin-conjugating enzyme E2S (UBE2S) belongs to the ubiquitin-conjugating enzyme family. UBE2S is able to form a thiol ester linkage with ubiquitin in a ubiquitin activating enzyme-dependent manner, a typical property of ubiquitin carrier proteins. UBE2S catalyzes the covalent attachment of ubiquitin to other proteins. UBE2S acts as a crucial factor of the anaphase promoting complex/cyclosome (APC/C), which is a cell cycle-regulated ubiquitin ligase that controls progression through mitosis. UBE2S acts by purposely elongating ''Lys-11''-linked polyubiquitin chains initiated by the E2 enzyme UBE2C/UBCH10 on APC/C substrates, augmenting the degradation of APC/C substrates by the proteasome and promoting mitotic exit. UBE2S also acts by elongating ubiquitin chains initiated by the E2 enzyme UBE2D1/UBCH5 in vitro; it is nevertheless uncertain whether UBE2D1/UBCH5 acts as an E2 enzyme for the APC/C in vivo. UBE2S is also involved in ubiquitination and consequent degradation of VHL, resu

Argininosuccinate lyase (ASL) is a member of the lyase 1 family. ASL is an enzyme which catalyzes the reversible breakdown of Argininosuccinate (ASA) yielding the amino acids arginine and fumarate. ASL which is located in the liver cytosol is the 4th enzyme of the urea cycle and involved in the biosynthesis of arginine in all species and the production of urea in ureotelic species. While Argininosuccinate synthetase (ASS) catalyzes the formation of argininosuccinate from citrulline and aspartate, ASL breaks down the newly formed argininosuccinate into L-arginine and fumarate. L-arginine continues within the urea cycle to form urea and orinthine, whereas fumarate can enter the citric acid cycle. ASL gene Mutations result in the autosomal recessive disorder argininosuccinic aciduria, or argininosuccinic acid lyase deficiency.

Phosphopantothenate-cysteine ligase (PPCS) catalyzes the first step in the biosynthesis of coenzyme A (CoA) from pantothenic acid (vitamin B5), which is a vital universal pathway in prokaryotes and eukaryotes. PPCS, being one of the last enzymes in this pathway, converts phosphopantothenate to phosphopantothenoylcysteine.

N-acetylneuraminate lyase (NPL) is an enzyme which catalyzes the chemical reaction (N-acetylneuraminate ->N-acetyl-D-mannosamine + pyruvate). NPL is a member of a family of lyases, specifically the oxo-acid-lyases, which cleave carbon-carbon bonds. NPL participates in amino sugars metabolism.