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General Transcription Factor IIF Polypeptide 2 (GTF2F2) is a general transcription initiation factor which binds to RNA polymerase II and helps engage it in the initiation complex in collaboration with TFIIB. GTF2F2 promotes transcription elongation. GTF2F2 shows ATP-dependent DNA-helicase activity.

Translocase of Outer Mitochondrial Membrane 34 (TOMM34) which is found in the cytoplasm and sometimes associated with the outer mitochondrial membrane is involved in the import of precursor proteins into mitochondria. TOMM34 has a chaperone-like activity, binding the mature portion of unfolded proteins and aiding their import into mitochondria. TOMM34 has a weak ATPase activity and contains 6 TPR repeats.

MTHFD2 plays a role as a homodimer which requires magnesium and inorganic phosphate. MTHFD2 has a pseudogene on chromosome 7 and owns 3 different enzymatic activities. Each of the activities catalyzes 1 of 3 sequential reactions in the interconversion of 1-carbon derivatives of tetrahydrofolate, which are substrates for methionine, thymidylate, and de novo purine syntheses.

Cytochrome c oxidase assembly factor 4 (COA4) is the last enzyme of the mitochondrial respiratory chain which needs a great number of accessory factors. COA4 is vital for oxidative phosphorylation and comprises multiple complexes including cytochrome c oxidase, assembled in macromolecular supercomplexes. COX4 is a protein-coding gene which defect in it causes an acute human encephalomyopathies.

Upstream Transcription Factor 1 (USF1) belongs to the basic helix-loop-helix leucine zipper family, and functions as a cellular transcription factor. USF1 activates transcription via pyrimidine-rich initiator (Inr) elements and E-box motifs. The USF1 gene has been linked to familial combined hyperlipidemia (FCHL). USF1 is a transcription factor which binds to a symmetrical DNA sequence (E-boxes) (5'-CACGTG-3') found in a various viral and cellular promoters.

TCEA1 is a member of the TFS-II family. TCEA1 binds to Pol II and operates to cleave the emerging transcript, thus unlocking the complex and permitting transcription to continue. TCEA1 is localized to the nucleus and holds three independently-folding domains that are essential for accurate binding to Pol II. The arresting sites in are able to trap a certain segment of elongating RNA polymerases that goes through, causing in a locked ternary complex. Cleavage of the emerging transcript by S-II enables the renewal of elongation from the new 3'-terminus.

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.

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.

Transcription elongation factor A protein-like 8 (TCEAL8) is a member of the TFS-II family and TFA subfamily. TCEAL8 is involved in transcriptional regulation and localized in nucleus. TFS-II family members contain TFA domains and act as nuclear phosphoproteins which control transcription in a promoter context-dependent mode. Numerous family members are found on the X chromosome.

ME2 catalyzes the oxidative decarboxylation of malate to pyruvate, malat + NAD(P)+? pyruvate + CO2 + NAD(P)H+, and is found both in eukaryotic and prokaryotic cells. Three different isoforms of ME are known to be in mammalian tissues: a strictly cytosolic NADP+-dependent enzyme, an NADP+-dependent mitochondriail isoform, and a mitochondrial isoenzyme that is able to use both NAD+ and NADP+ but is more effective with NAD+. The mammalian isoforms size is about 62-64 kDa. A native size of 240,000 Da proposes a tetrameric structure for the active enzyme.
Mitochondrial NAD+-dependent ME 2 activity is seen in tissues that experience many cell divisions, like spleen, thymus, and the basal cells of the small intestinal mucosa. ME2 is also expressed all through the rapid cleavage stages of early Xenopus development. Activity for this isoform is low or nonexistent in brain, muscle, and normal and regenerating liver tissue from rat but was observed in rat adrenal cortex, pigeon and human skeletal muscle, and in heart muscle of some species. In addition, it is expressed in mitochondria of all tumor cells inspected to detain ascites tumors, hepatoma cells, and a variety of other tumors and transformed cell lines.

MRPS25, a 28S subunit protein, is a member of the ribosomal protein S5P family. An equivalent pseudogene is located on chromosome 4.

Mitochondrial antiviral signaling protein (MAVS) is vital for innate immune defense against viruses. MAVS is an intermediary protein essential in the virus-triggered IFN-beta signaling pathways. MAVS is involved in activation of transcription factors that regulate expression of IFN-beta and contributes to antiviral immunity.

Mortality factor 4-like protein 1 (MORF4L1) is a member of the MRG family. MORF4L1 is a component of the NuA4 histone acetyltransferase (HAT) complex which is involved in transcriptional activation of select genes mostly by acetylation of nucleosomal histones H4 and H2A. MORF4L1 is a transcription factor expressed in various human tissues, and its orthologs have been found in many other eukaryotes which comprise the MRG protein family. The C-terminal part of MORF4L1 forms a conserved MRG domain that is involved in interactions with the tumor suppressor protein retinoblastoma and a nucleoprotein.

The GAGA factor is a sequence-specific DNA-binding protein, which participates in the regulation of the expression of a variety of different classes of genes in Drosophila such as many developmentally regulated genes, stress induced genes, and cell cycle regulated genes, as well as housekeeping genes. GAGA contains a C-terminal glutamine-rich domain and a highly conserved N-terminal POZ domain which reported to be involved in self-oligomerization in a number of other POZ domain containing proteins. In case of GAGA protein, the N-terminal POZ domain mediates the formation of oligomers both in vitro and in vivo.

NT5M is a member of the 5'(3')-deoxyribonucleotidase family. NT5M localizes to the mitochondrial matrix. The NT5M enzyme dephosphorylates the 5'- and 2'(3')-phosphates of uracil and thymine deoxyribonucleotides. The NT5M gene is located on chromosome 17 p11.2 in the critical region deleted in the Smith-Magenis syndrome (SMS), a genetic disease of unidentified etiology.

Mammalian mitochondrial ribosomal proteins are encoded by nuclear genes and aid in protein synthesis within the mitochondrion. Mitochondrial ribosomes (mitoribosomes) comprised of a small 28S subunit and a large 39S subunit. Among different species, the proteins comprising the mitoribosome vary greatly in sequence, and sometimes in biochemical properties, thus preventing simple recognition by sequence homology. Mitochondrial Ribosomal Protein L2 (MRPL2) is a 39S subunit protein which is a member of the EcoL2 ribosomal protein family.

Thioredoxin-2 is a low molecular weight redox protein. TRX2 contains a redox active disulfide/dithiol group within the conserved Cys-Gly-Pro-Cys active site. The TXN2 is involved in the regulation of the mitochondrial membrane potential and in protection against oxidant-induced apoptosis. Upon stimulation of Fas, TXN2 mediates denitrosylation of mitochondria-associated caspase-3, a process required for caspase-3 activation, and promoted apoptosis.
TRX2 is important at low oxidative stress conditions.
MTRX is involved in the regulation of the mitochondrial membrane potential and cell death. Mitochondrial thioredoxin plays an important roles in protection against oxidant-induced apoptosis. Thioredoxin1 and thioredoxin2 have opposed regulatory functions on hypoxia-inducible factor-1alpha.

F-ATPase delta (ATP5D) catalyzes ATP synthesis, employing an electrochemical gradient of protons across the inner membrane during oxidative phosphorylation. ATP synthase is composed of 2 linked multi-subunit complexes: F1-the soluble catalytic core and Fo- the membrane-spanning component, which comprise the proton channel. The catalytic portion of mitochondrial ATP synthase consists of five different subunits (alpha, beta, gamma, delta, and epsilon) assembled with a stoichiometry of 3 alphas, 3 betas, and a single representative of the other three. The proton channel consists of three main subunits-a, b, c. ATP5D is the delta subunit of the catalytic core.

Mammalian mitochondrial ribosomal proteins are encoded by nuclear genes and help in protein synthesis within the mitochondrion. Mitochondrial ribosomes (mitoribosomes) consist of a small 28S subunit and a large 39S subunit and have about 75% protein to rRNA composition compared to prokaryotic ribosomes, where this ratio is reversed. Mitochondrial Ribosomal Protein S2 (MRPS2) is a 28S subunit protein which is a part of the ribosomal protein S2 family and comprises a 12S rRNA and about 30 distinct proteins.

CKMT1A is in charge of the transfer of high energy phosphate from mitochondria to the cytosolic carrier, creatine. CKMT1A is a member of the creatine kinase isoenzyme family and exists as two isoenzymes, sarcomeric MtCK and ubiquitous MtCK, encoded by separate genes. Mitochondrial creatine kinase arises in two different oligomeric forms: dimers and octamers, unlike the exclusively dimeric cytosolic creatine kinase isoenzymes. Numerous malignant cancers with poor prognosis have displayed overexpression of ubiquitous mitochondrial creatine kinase which is linked to high energy turnover and inability to remove cancer cells through apoptosis.

OXSM, a beta-ketoacyl synthetase, is essential for elongation of fatty acid chains in the mitochondria. Alternatively spliced transcript variants were found.

Mammalian mitochondrial ribosomal proteins are encoded by nuclear genes and assist in protein synthesis within the mitochondrion. Mitochondrial ribosomes (mitoribosomes) consist of a small 28S subunit and a large 39S subunit (MRPL13 is a 39S subunit protein) and have an estimated 75% protein to rRNA composition compared to prokaryotic ribosomes, where this ratio is reversed. An additional difference between mammalian mitoribosomes and prokaryotic ribosomes is that the second contain a 5S rRNA. Among various species, the proteins comprising the mitoribosome differ greatly in sequence, and sometimes in biochemical properties, which prevents easy recognition by sequence homology.

ATPase Transporting, Lysosomal V1 Subunit F (ATP6V1F) is a component of vacuolar ATPase (V-ATPase); it is a multi-subunit enzyme, which mediates acidification of eukaryotic intracellular organelles. V-ATPase dependent organelle acidification is required for such intracellular processes as protein sorting, zymogen activation, receptor-mediated endocytosis, and synaptic vesicle proton gradient generation. V-ATPase is comprised of a cytosolic V1 domain and a transmembrane V0 domain. The V1 domain contains 3 A and 3 B subunits, 2 G subunits as well as the C, D, E, F, and H subunits. The V1 domain has the ATP catalytic site. The V0 domain consists of 5 different subunits: a, c, c', c', and d.

NADH dehydrogenase [ubiquinone] 1 alpha subcomplex assembly factor 4 (NDUFAF4) is involved in the compilation of mitochondrial NADH: ubiquinone oxidoreductase complex (complex I). In addition, NDUFAF4 is involved in cell proliferation and survival of hormone-dependent tumor cells. NDUFAF4 may also be a regulator of breast tumor cell invasion. NDUFAF4 gene mutations cause the mitochondrial complex I deficiency.