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Aliases for TK2 Gene

Aliases for TK2 Gene

  • Thymidine Kinase 2, Mitochondrial 2 3
  • Mt-TK 3 4
  • EC 4
  • MTDPS2 3
  • SCA31 3
  • MTTK 3

External Ids for TK2 Gene

Previous GeneCards Identifiers for TK2 Gene

  • GC16M057239
  • GC16M066921
  • GC16M066280
  • GC16M066320
  • GC16M065102
  • GC16M066543
  • GC16M052417
  • GC16M066505
  • GC16M066506

Summaries for TK2 Gene

Entrez Gene Summary for TK2 Gene

  • This gene encodes a deoxyribonucleoside kinase that specifically phosphorylates thymidine, deoxycytidine, and deoxyuridine. The encoded enzyme localizes to the mitochondria and is required for mitochondrial DNA synthesis. Mutations in this gene are associated with a myopathic form of mitochondrial DNA depletion syndrome. Alternate splicing results in multiple transcript variants encoding distinct isoforms, some of which lack transit peptide, so are not localized to mitochondria. [provided by RefSeq, Dec 2012]

GeneCards Summary for TK2 Gene

TK2 (Thymidine Kinase 2, Mitochondrial) is a Protein Coding gene. Diseases associated with TK2 include mitochondrial dna depletion syndrome, myopathic form and mitochondrial dna depletion syndrome 2. Among its related pathways are Cell Cycle, Mitotic and Metabolism. GO annotations related to this gene include nucleoside kinase activity and thymidine kinase activity. An important paralog of this gene is DGUOK.

UniProtKB/Swiss-Prot for TK2 Gene

  • Deoxyribonucleoside kinase that phosphorylates thymidine, deoxycytidine, and deoxyuridine. Also phosphorylates anti-viral and anti-cancer nucleoside analogs

No data available for Tocris Summary , Gene Wiki entry , PharmGKB "VIP" Summary , fRNAdb sequence ontologies and piRNA Summary for TK2 Gene

Genomics for TK2 Gene

Regulatory Elements for TK2 Gene

Epigenetics Products

  • DNA Methylation CpG Assay Predesigned for Pyrosequencing in human,mouse,rat

Genomic Location for TK2 Gene

66,508,003 bp from pter
66,552,544 bp from pter
44,542 bases
Minus strand

Genomic View for TK2 Gene

UCSC Golden Path with GeneCards custom track
Cytogenetic band:
Genomic Location for TK2 Gene
GeneLoc Logo Genomic Neighborhood Exon StructureGene Density

RefSeq DNA sequence for TK2 Gene

Proteins for TK2 Gene

  • Protein details for TK2 Gene (UniProtKB/Swiss-Prot)

    Protein Symbol:
    Recommended name:
    Thymidine kinase 2, mitochondrial
    Protein Accession:
    Secondary Accessions:
    • B4DGJ7
    • B4DZK7
    • B7ZAB1
    • E9PH08
    • O15238

    Protein attributes for TK2 Gene

    265 amino acids
    Molecular mass:
    31005 Da
    Quaternary structure:
    • Monomer

    Alternative splice isoforms for TK2 Gene


neXtProt entry for TK2 Gene

Proteomics data for TK2 Gene at MOPED

Post-translational modifications for TK2 Gene

  • Modification sites at PhosphoSitePlus
  • Modification sites at neXtProt

No data available for DME Specific Peptides for TK2 Gene

Domains & Families for TK2 Gene

Protein Domains for TK2 Gene

Graphical View of Domain Structure for InterPro Entry



  • Belongs to the DCK/DGK family.
  • Belongs to the DCK/DGK family.
genes like me logo Genes that share domains with TK2: view

No data available for Gene Families for TK2 Gene

Function for TK2 Gene

Molecular function for TK2 Gene

GENATLAS Biochemistry:
thymidine kinase 2,pyrimidine salvage pathway,mitochondrial,involved in the activation of chemotherapeutic nucleoside analogues
UniProtKB/Swiss-Prot CatalyticActivity:
ATP + thymidine = ADP + thymidine 5-phosphate
UniProtKB/Swiss-Prot Function:
Deoxyribonucleoside kinase that phosphorylates thymidine, deoxycytidine, and deoxyuridine. Also phosphorylates anti-viral and anti-cancer nucleoside analogs

Enzyme Numbers (IUBMB) for TK2 Gene

Gene Ontology (GO) - Molecular Function for TK2 Gene

GO ID Qualified GO term Evidence PubMed IDs
GO:0004137 deoxycytidine kinase activity IEA --
GO:0004797 thymidine kinase activity IEA --
GO:0005524 ATP binding IEA --
GO:0019206 nucleoside kinase activity --
genes like me logo Genes that share ontologies with TK2: view
genes like me logo Genes that share phenotypes with TK2: view

Animal Models for TK2 Gene

MGI Knock Outs for TK2:

Animal Model Products

miRNA for TK2 Gene

miRTarBase miRNAs that target TK2

No data available for Transcription Factor Targets and HOMER Transcription for TK2 Gene

Localization for TK2 Gene

Subcellular locations from UniProtKB/Swiss-Prot for TK2 Gene


Subcellular locations from

Jensen Localization Image for TK2 Gene COMPARTMENTS Subcellular localization image for TK2 gene
Compartment Confidence
mitochondrion 5
cytosol 1

Gene Ontology (GO) - Cellular Components for TK2 Gene

GO ID Qualified GO term Evidence PubMed IDs
GO:0005739 mitochondrion --
GO:0005743 mitochondrial inner membrane IEA --
GO:0005759 mitochondrial matrix TAS --
genes like me logo Genes that share ontologies with TK2: view

Pathways & Interactions for TK2 Gene

genes like me logo Genes that share pathways with TK2: view

Interacting Proteins for TK2 Gene

Gene Ontology (GO) - Biological Process for TK2 Gene

GO ID Qualified GO term Evidence PubMed IDs
GO:0006139 nucleobase-containing compound metabolic process TAS 9079672
GO:0006206 pyrimidine nucleobase metabolic process TAS --
GO:0006264 mitochondrial DNA replication IEA --
GO:0009157 deoxyribonucleoside monophosphate biosynthetic process IEA --
GO:0009165 nucleotide biosynthetic process IEA --
genes like me logo Genes that share ontologies with TK2: view

No data available for SIGNOR curated interactions for TK2 Gene

Drugs & Compounds for TK2 Gene

(15) Drugs for TK2 Gene - From: NovoSeek, HMDB, and DrugBank

Name Status Disease Links Group Role Mechanism of Action Clinical Trials
Floxuridine Approved Pharma Antineoplastic antimetabolite, RNA and DNA synthesis inhibitor, Inhibitor of thymidylate synthetase; anticancer agent 47
Adenosine triphosphate Approved Nutra 0
Cytarabine Approved, Investigational Pharma 995
Gemcitabine Approved Pharma Ribonucleotide reductase and DNA synthesis inhibitor, Nucleoside Analogs 1800
Zidovudine Approved Pharma 489

(19) Additional Compounds for TK2 Gene - From: HMDB and NovoSeek

Name Synonyms Role CAS Number PubChem IDs PubMed IDs
5-Fluorodeoxyuridine monophosphate
  • Adenosindiphosphorsaeure
  • Adenosine 5'-pyrophosphate
  • Adenosine diphosphate
  • Adenosine pyrophosphate
  • Adenosine-5'-diphosphate
Antagonist, Gating inhibitor 58-64-0
genes like me logo Genes that share compounds with TK2: view

Transcripts for TK2 Gene

Unigene Clusters for TK2 Gene

Thymidine kinase 2, mitochondrial:
Representative Sequences:

Alternative Splicing Database (ASD) splice patterns (SP) for TK2 Gene

No ASD Table

Relevant External Links for TK2 Gene

GeneLoc Exon Structure for
ECgene alternative splicing isoforms for

Expression for TK2 Gene

mRNA expression in normal human tissues for TK2 Gene

Protein differential expression in normal tissues from HIPED for TK2 Gene

This gene is overexpressed in Peripheral blood mononuclear cells (7.3) and Skin (6.1).

Integrated Proteomics: protein expression in normal tissues and cell lines from ProteomicsDB and MOPED for TK2 Gene

SOURCE GeneReport for Unigene cluster for TK2 Gene Hs.512619

mRNA Expression by UniProt/SwissProt for TK2 Gene

Tissue specificity: Predominantly expressed in liver, pancreas, muscle, and brain
genes like me logo Genes that share expression patterns with TK2: view

Protein tissue co-expression partners for TK2 Gene

Primer Products

In Situ Assay Products

No data available for mRNA expression in embryonic tissues and stem cells from LifeMap Discovery and mRNA differential expression in normal tissues for TK2 Gene

Orthologs for TK2 Gene

This gene was present in the common ancestor of animals.

Orthologs for TK2 Gene

Organism Taxonomy Gene Similarity Type Details
(Bos Taurus)
Mammalia TK2 35
  • 84.99 (n)
  • 83.21 (a)
TK2 36
  • 71 (a)
(Canis familiaris)
Mammalia TK2 35
  • 87.95 (n)
  • 86.75 (a)
TK2 36
  • 83 (a)
(Mus musculus)
Mammalia Tk2 35
  • 83.02 (n)
  • 82.26 (a)
Tk2 16
Tk2 36
  • 79 (a)
(Pan troglodytes)
Mammalia TK2 35
  • 99.37 (n)
  • 99.25 (a)
TK2 36
  • 86 (a)
(Rattus norvegicus)
Mammalia Tk2 35
  • 83.02 (n)
  • 81.51 (a)
(Monodelphis domestica)
Mammalia TK2 36
  • 76 (a)
(Ornithorhynchus anatinus)
Mammalia TK2 36
  • 69 (a)
(Gallus gallus)
Aves TK2 35
  • 73.09 (n)
  • 73.49 (a)
TK2 36
  • 73 (a)
(Anolis carolinensis)
Reptilia -- 36
  • 70 (a)
-- 36
  • 72 (a)
tropical clawed frog
(Silurana tropicalis)
Amphibia Str.424 35
tk2 35
  • 69.33 (n)
  • 70.42 (a)
African clawed frog
(Xenopus laevis)
Amphibia LOC398276 35
(Danio rerio)
Actinopterygii Dr.18401 35
tk2 35
  • 68.95 (n)
  • 72.06 (a)
tk2 36
  • 58 (a)
fruit fly
(Drosophila melanogaster)
Insecta dnk 37
  • 44 (a)
dnk 35
  • 51.14 (n)
  • 46.57 (a)
dnk 36
  • 39 (a)
African malaria mosquito
(Anopheles gambiae)
Insecta AgaP_AGAP001585 35
  • 56.35 (n)
  • 50.48 (a)
Species with no ortholog for TK2:
  • A. gosspyii yeast (Ashbya gossypii)
  • Actinobacteria (Mycobacterium tuberculosis)
  • Alicante grape (Vitis vinifera)
  • alpha proteobacteria (Wolbachia pipientis)
  • amoeba (Dictyostelium discoideum)
  • Archea (Pyrococcus horikoshii)
  • baker's yeast (Saccharomyces cerevisiae)
  • barley (Hordeum vulgare)
  • beta proteobacteria (Neisseria meningitidis)
  • bread mold (Neurospora crassa)
  • Chromalveolata (Phytophthora infestans)
  • common water flea (Daphnia pulex)
  • corn (Zea mays)
  • E. coli (Escherichia coli)
  • filamentous fungi (Aspergillus nidulans)
  • Firmicute bacteria (Streptococcus pneumoniae)
  • fission yeast (Schizosaccharomyces pombe)
  • green algae (Chlamydomonas reinhardtii)
  • honey bee (Apis mellifera)
  • K. lactis yeast (Kluyveromyces lactis)
  • loblloly pine (Pinus taeda)
  • malaria parasite (Plasmodium falciparum)
  • medicago trunc (Medicago Truncatula)
  • moss (Physcomitrella patens)
  • orangutan (Pongo pygmaeus)
  • pig (Sus scrofa)
  • rainbow trout (Oncorhynchus mykiss)
  • rice (Oryza sativa)
  • rice blast fungus (Magnaporthe grisea)
  • schistosome parasite (Schistosoma mansoni)
  • sea anemone (Nematostella vectensis)
  • sea squirt (Ciona intestinalis)
  • sea squirt (Ciona savignyi)
  • sea urchin (Strongylocentrotus purpuratus)
  • sorghum (Sorghum bicolor)
  • soybean (Glycine max)
  • stem rust fungus (Puccinia graminis)
  • sugarcane (Saccharum officinarum)
  • thale cress (Arabidopsis thaliana)
  • tomato (Lycopersicon esculentum)
  • toxoplasmosis (Toxoplasma gondii)
  • Trichoplax (Trichoplax adhaerens)
  • wheat (Triticum aestivum)
  • worm (Caenorhabditis elegans)

Evolution for TK2 Gene

Gene Tree for TK2 (if available)
Gene Tree for TK2 (if available)

Paralogs for TK2 Gene

Paralogs for TK2 Gene

genes like me logo Genes that share paralogs with TK2: view

Variants for TK2 Gene

Sequence variations from dbSNP and Humsavar for TK2 Gene

SNP ID Clin Chr 16 pos Sequence Context AA Info Type MAF
rs28171 -- 66,537,518(-) AGGGA(A/G)CGTAC intron-variant
rs37175 -- 66,520,103(+) TGCAG(C/T)ACAGA intron-variant
rs37176 -- 66,528,097(+) GACAG(C/G)GTGGT intron-variant
rs37177 -- 66,532,336(+) cagtg(A/G)ctcat intron-variant
rs384261 -- 66,547,696(+) AGACA(A/G)ACCTC intron-variant

Structural Variations from Database of Genomic Variants (DGV) for TK2 Gene

Variant ID Type Subtype PubMed ID
nsv906785 CNV Loss 21882294
nsv906786 CNV Loss 21882294
nsv1839 CNV Insertion 18451855
esv2676087 CNV Deletion 23128226

Variation tolerance for TK2 Gene

Residual Variation Intolerance Score: 52.58% of all genes are more intolerant (likely to be disease-causing)
Gene Damage Index Score: 6.24; 76.25% of all genes are more intolerant (likely to be disease-causing)

Relevant External Links for TK2 Gene

HapMap Linkage Disequilibrium report
Human Gene Mutation Database (HGMD)

No data available for Polymorphic Variants from UniProtKB/Swiss-Prot for TK2 Gene

Disorders for TK2 Gene

MalaCards: The human disease database

(9) MalaCards diseases for TK2 Gene - From: OMIM, ClinVar, GeneTests, Orphanet, Swiss-Prot, DISEASES, NovoSeek, and GeneCards

- elite association
Search TK2 in MalaCards View complete list of genes associated with diseases


  • Mitochondrial DNA depletion syndrome 2 (MTDPS2) [MIM:609560]: A disorder due to mitochondrial dysfunction characterized by childhood onset of muscle weakness associated with depletion of mtDNA in skeletal muscle. There is wide clinical variability; some patients have onset in infancy and show a rapidly progressive course with early death due to respiratory failure, whereas others have later onset of a slowly progressive myopathy. {ECO:0000269 PubMed:11687801, ECO:0000269 PubMed:12391347, ECO:0000269 PubMed:15639197, ECO:0000269 PubMed:15907288, ECO:0000269 PubMed:25446393}. Note=The disease is caused by mutations affecting the gene represented in this entry.

Relevant External Links for TK2

Genetic Association Database (GAD)
Human Genome Epidemiology (HuGE) Navigator
Atlas of Genetics and Cytogenetics in Oncology and Haematology:
genes like me logo Genes that share disorders with TK2: view

No data available for Genatlas for TK2 Gene

Publications for TK2 Gene

  1. Loss of thymidine kinase 2 alters neuronal bioenergetics and leads to neurodegeneration. (PMID: 20123860) Bartesaghi S. … Nicotera P. (Hum. Mol. Genet. 2010) 23 67
  2. Cytotoxic activity of gemcitabine in cultured cell lines derived from histologically different types of bladder cancer: role of thymidine kinase 2. (PMID: 19660438) Damaraju S. … Cass C.E. (Biochem. Pharmacol. 2010) 23 67
  3. Application of oligonucleotide array CGH to the simultaneous detection of a deletion in the nuclear TK2 gene and mtDNA depletion. (PMID: 19815440) Zhang S. … Wong L.J. (Mol. Genet. Metab. 2010) 23 67
  4. Two novel mutations in thymidine kinase-2 cause early onset fatal encephalomyopathy and severe mtDNA depletion. (PMID: 20083405) Lesko N. … Larsson N.G. (Neuromuscul. Disord. 2010) 23 67
  5. 3'-[4-Aryl-(1,2,3-triazol-1-yl)]-3'-deoxythymidine analogues as potent and selective inhibitors of human mitochondrial thymidine kinase. (PMID: 20218622) Van Poecke S. … Van Calenbergh S. (J. Med. Chem. 2010) 23 67

Products for TK2 Gene

Sources for TK2 Gene

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