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Protein

Thymidine kinase 2, mitochondrial

Gene

TK2

Organism
Homo sapiens (Human)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

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

Catalytic activityi

ATP + thymidine = ADP + thymidine 5'-phosphate.

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Binding sitei81SubstrateBy similarity1
Binding sitei99SubstrateBy similarity1
Binding sitei110SubstrateBy similarity1
Active sitei133Proton acceptorSequence analysis1
Binding sitei134SubstrateBy similarity1
Binding sitei201SubstrateBy similarity1

Regions

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Nucleotide bindingi57 – 65ATPBy similarity9

GO - Molecular functioni

  • ATP binding Source: UniProtKB-KW
  • deoxycytidine kinase activity Source: Ensembl
  • nucleoside kinase activity Source: Reactome
  • thymidine kinase activity Source: ProtInc

GO - Biological processi

Complete GO annotation...

Keywords - Molecular functioni

Kinase, Transferase

Keywords - Biological processi

DNA synthesis

Keywords - Ligandi

ATP-binding, Nucleotide-binding

Enzyme and pathway databases

BioCyciMetaCyc:HS09420-MONOMER.
ZFISH:HS09420-MONOMER.
BRENDAi2.7.1.21. 2681.
ReactomeiR-HSA-113510. E2F mediated regulation of DNA replication.
R-HSA-69205. G1/S-Specific Transcription.
R-HSA-73614. Pyrimidine salvage reactions.
SABIO-RKO00142.

Names & Taxonomyi

Protein namesi
Recommended name:
Thymidine kinase 2, mitochondrial (EC:2.7.1.21)
Alternative name(s):
Mt-TK
Gene namesi
Name:TK2
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
Proteomesi
  • UP000005640 Componenti: Chromosome 16

Organism-specific databases

HGNCiHGNC:11831. TK2.

Subcellular locationi

GO - Cellular componenti

Complete GO annotation...

Keywords - Cellular componenti

Mitochondrion

Pathology & Biotechi

Involvement in diseasei

Mitochondrial DNA depletion syndrome 2 (MTDPS2)5 Publications
The disease is caused by mutations affecting the gene represented in this entry.
Disease descriptionA 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.
See also OMIM:609560
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Natural variantiVAR_01941953I → M in MTDPS2. 1 PublicationCorresponds to variant rs137854432dbSNPEnsembl.1
Natural variantiVAR_02379064T → M in MTDPS2. 1 PublicationCorresponds to variant rs281865487dbSNPEnsembl.1
Natural variantiVAR_019420108T → M in MTDPS2; reduction of activity. 2 PublicationsCorresponds to variant rs137854431dbSNPEnsembl.1
Natural variantiVAR_072789117M → V in MTDPS2; severe form of combined brain and muscular atrophy; depletion of mtDNA in skeletal muscle; normal residual mtDNA in blood and fibroblasts. 1 Publication1
Natural variantiVAR_019421121H → N in MTDPS2. 2 PublicationsCorresponds to variant rs137854429dbSNPEnsembl.1
Natural variantiVAR_072790139A → V in MTDPS2; severe form of combined brain and muscular atrophy; depletion of mtDNA in skeletal muscle; normal residual mtDNA in blood and fibroblasts. 1 PublicationCorresponds to variant rs281865494dbSNPEnsembl.1
Natural variantiVAR_023791183R → W in MTDPS2. 1 PublicationCorresponds to variant rs137886900dbSNPEnsembl.1
Natural variantiVAR_023792192R → K in MTDPS2; reduction of activity. 1 PublicationCorresponds to variant rs281865496dbSNPEnsembl.1
Natural variantiVAR_019422212I → N in MTDPS2. 1 PublicationCorresponds to variant rs137854430dbSNPEnsembl.1

Keywords - Diseasei

Disease mutation

Organism-specific databases

DisGeNETi7084.
MalaCardsiTK2.
MIMi609560. phenotype.
OpenTargetsiENSG00000166548.
Orphaneti254886. Autosomal recessive progressive external ophthalmoplegia.
254875. Mitochondrial DNA depletion syndrome, myopathic form.
PharmGKBiPA36535.

Chemistry databases

ChEMBLiCHEMBL4580.

Polymorphism and mutation databases

BioMutaiTK2.

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Transit peptidei1 – 33MitochondrionAdd BLAST33
ChainiPRO_000001684234 – 265Thymidine kinase 2, mitochondrialAdd BLAST232

Proteomic databases

MaxQBiO00142.
PaxDbiO00142.
PeptideAtlasiO00142.
PRIDEiO00142.

PTM databases

iPTMnetiO00142.
PhosphoSitePlusiO00142.

Expressioni

Tissue specificityi

Predominantly expressed in liver, pancreas, muscle, and brain.

Gene expression databases

BgeeiENSG00000166548.
CleanExiHS_TK2.
ExpressionAtlasiO00142. baseline and differential.
GenevisibleiO00142. HS.

Organism-specific databases

HPAiHPA041162.

Interactioni

Subunit structurei

Monomer.

Protein-protein interaction databases

BioGridi112939. 8 interactors.
STRINGi9606.ENSP00000414334.

Chemistry databases

BindingDBiO00142.

Structurei

3D structure databases

ProteinModelPortaliO00142.
SMRiO00142.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Sequence similaritiesi

Belongs to the DCK/DGK family.Curated

Keywords - Domaini

Transit peptide

Phylogenomic databases

eggNOGiKOG4235. Eukaryota.
COG1428. LUCA.
GeneTreeiENSGT00510000046588.
HOGENOMiHOG000006872.
HOVERGENiHBG006216.
InParanoidiO00142.
KOiK00857.
PhylomeDBiO00142.
TreeFamiTF324413.

Family and domain databases

Gene3Di3.40.50.300. 1 hit.
InterProiIPR002624. DCK/DGK.
IPR031314. DNK_dom.
IPR027417. P-loop_NTPase.
[Graphical view]
PfamiPF01712. dNK. 1 hit.
[Graphical view]
PIRSFiPIRSF000705. DNK. 1 hit.
SUPFAMiSSF52540. SSF52540. 1 hit.

Sequences (5)i

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

This entry describes 5 isoformsi produced by alternative splicing. AlignAdd to basket

Isoform Long (identifier: O00142-1) [UniParc]FASTAAdd to basket

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

« Hide

        10         20         30         40         50
MLLWPLRGWA ARALRCFGPG SRGSPASGPG PRRVQRRAWP PDKEQEKEKK
60 70 80 90 100
SVICVEGNIA SGKTTCLEFF SNATDVEVLT EPVSKWRNVR GHNPLGLMYH
110 120 130 140 150
DASRWGLTLQ TYVQLTMLDR HTRPQVSSVR LMERSIHSAR YIFVENLYRS
160 170 180 190 200
GKMPEVDYVV LSEWFDWILR NMDVSVDLIV YLRTNPETCY QRLKKRCREE
210 220 230 240 250
EKVIPLEYLE AIHHLHEEWL IKGSLFPMAA PVLVIEADHH MERMLELFEQ
260
NRDRILTPEN RKHCP
Length:265
Mass (Da):31,005
Last modified:July 28, 2009 - v4
Checksum:i1E9CB62D0321A992
GO
Isoform Short (identifier: O00142-2) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     1-41: MLLWPLRGWAARALRCFGPGSRGSPASGPGPRRVQRRAWPP → MGAFCQRPSS

Note: No experimental confirmation available.
Show »
Length:234
Mass (Da):27,562
Checksum:iBA62F86B35942E34
GO
Isoform 3 (identifier: O00142-3) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     53-77: Missing.

Note: No experimental confirmation available.
Show »
Length:240
Mass (Da):28,374
Checksum:i5BBDA88F49F0F331
GO
Isoform 4 (identifier: O00142-4) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     78-95: Missing.

Note: No experimental confirmation available.
Show »
Length:247
Mass (Da):28,920
Checksum:i9EB1F18D680A66BB
GO
Isoform 5 (identifier: O00142-5) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     1-97: Missing.

Note: No experimental confirmation available.
Show »
Length:168
Mass (Da):20,281
Checksum:i436EAB164C5784EE
GO

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti37R → Y AA sequence (PubMed:9989599).Curated1
Sequence conflicti49K → E in BAG57808 (PubMed:14702039).Curated1
Sequence conflicti61S → G in AAC51167 (PubMed:9079672).Curated1
Sequence conflicti206L → P in BAG57808 (PubMed:14702039).Curated1
Sequence conflicti238D → DH in CAA71523 (PubMed:9989599).Curated1
Sequence conflicti241Missing in AAC51167 (PubMed:9079672).Curated1
Sequence conflicti251N → S in BAG57808 (PubMed:14702039).Curated1

Natural variant

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Natural variantiVAR_01941953I → M in MTDPS2. 1 PublicationCorresponds to variant rs137854432dbSNPEnsembl.1
Natural variantiVAR_02379064T → M in MTDPS2. 1 PublicationCorresponds to variant rs281865487dbSNPEnsembl.1
Natural variantiVAR_019420108T → M in MTDPS2; reduction of activity. 2 PublicationsCorresponds to variant rs137854431dbSNPEnsembl.1
Natural variantiVAR_072789117M → V in MTDPS2; severe form of combined brain and muscular atrophy; depletion of mtDNA in skeletal muscle; normal residual mtDNA in blood and fibroblasts. 1 Publication1
Natural variantiVAR_019421121H → N in MTDPS2. 2 PublicationsCorresponds to variant rs137854429dbSNPEnsembl.1
Natural variantiVAR_072790139A → V in MTDPS2; severe form of combined brain and muscular atrophy; depletion of mtDNA in skeletal muscle; normal residual mtDNA in blood and fibroblasts. 1 PublicationCorresponds to variant rs281865494dbSNPEnsembl.1
Natural variantiVAR_023791183R → W in MTDPS2. 1 PublicationCorresponds to variant rs137886900dbSNPEnsembl.1
Natural variantiVAR_023792192R → K in MTDPS2; reduction of activity. 1 PublicationCorresponds to variant rs281865496dbSNPEnsembl.1
Natural variantiVAR_019422212I → N in MTDPS2. 1 PublicationCorresponds to variant rs137854430dbSNPEnsembl.1

Alternative sequence

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Alternative sequenceiVSP_0546061 – 97Missing in isoform 5. 1 PublicationAdd BLAST97
Alternative sequenceiVSP_0030281 – 41MLLWP…RAWPP → MGAFCQRPSS in isoform Short. 1 PublicationAdd BLAST41
Alternative sequenceiVSP_04350353 – 77Missing in isoform 3. 1 PublicationAdd BLAST25
Alternative sequenceiVSP_04445978 – 95Missing in isoform 4. 1 PublicationAdd BLAST18

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U77088 mRNA. Translation: AAC51167.1.
Y10498 mRNA. Translation: CAA71523.3.
AK294627 mRNA. Translation: BAG57808.1.
AK302976 mRNA. Translation: BAG64119.1.
AK316226 mRNA. Translation: BAH14597.1.
AC010542 Genomic DNA. No translation available.
CH471092 Genomic DNA. Translation: EAW83013.1.
CH471092 Genomic DNA. Translation: EAW83015.1.
CCDSiCCDS10805.2. [O00142-1]
CCDS54016.1. [O00142-3]
CCDS54017.1. [O00142-4]
CCDS54018.1. [O00142-2]
CCDS61955.1. [O00142-5]
RefSeqiNP_001166114.1. NM_001172643.1. [O00142-2]
NP_001166115.1. NM_001172644.1. [O00142-3]
NP_001258864.1. NM_001271935.1.
NP_001258979.1. NM_001272050.1. [O00142-5]
NP_004605.4. NM_004614.4. [O00142-1]
UniGeneiHs.512619.

Genome annotation databases

EnsembliENST00000299697; ENSP00000299697; ENSG00000166548. [O00142-1]
ENST00000525974; ENSP00000434594; ENSG00000166548. [O00142-5]
ENST00000527284; ENSP00000435312; ENSG00000166548. [O00142-2]
ENST00000527800; ENSP00000433770; ENSG00000166548. [O00142-5]
ENST00000544898; ENSP00000440898; ENSG00000166548. [O00142-1]
ENST00000545043; ENSP00000438143; ENSG00000166548. [O00142-3]
ENST00000563369; ENSP00000463560; ENSG00000166548. [O00142-5]
ENST00000620035; ENSP00000483833; ENSG00000166548. [O00142-4]
GeneIDi7084.
KEGGihsa:7084.
UCSCiuc002eor.4. human. [O00142-1]

Keywords - Coding sequence diversityi

Alternative splicing

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U77088 mRNA. Translation: AAC51167.1.
Y10498 mRNA. Translation: CAA71523.3.
AK294627 mRNA. Translation: BAG57808.1.
AK302976 mRNA. Translation: BAG64119.1.
AK316226 mRNA. Translation: BAH14597.1.
AC010542 Genomic DNA. No translation available.
CH471092 Genomic DNA. Translation: EAW83013.1.
CH471092 Genomic DNA. Translation: EAW83015.1.
CCDSiCCDS10805.2. [O00142-1]
CCDS54016.1. [O00142-3]
CCDS54017.1. [O00142-4]
CCDS54018.1. [O00142-2]
CCDS61955.1. [O00142-5]
RefSeqiNP_001166114.1. NM_001172643.1. [O00142-2]
NP_001166115.1. NM_001172644.1. [O00142-3]
NP_001258864.1. NM_001271935.1.
NP_001258979.1. NM_001272050.1. [O00142-5]
NP_004605.4. NM_004614.4. [O00142-1]
UniGeneiHs.512619.

3D structure databases

ProteinModelPortaliO00142.
SMRiO00142.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi112939. 8 interactors.
STRINGi9606.ENSP00000414334.

Chemistry databases

BindingDBiO00142.
ChEMBLiCHEMBL4580.

PTM databases

iPTMnetiO00142.
PhosphoSitePlusiO00142.

Polymorphism and mutation databases

BioMutaiTK2.

Proteomic databases

MaxQBiO00142.
PaxDbiO00142.
PeptideAtlasiO00142.
PRIDEiO00142.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENST00000299697; ENSP00000299697; ENSG00000166548. [O00142-1]
ENST00000525974; ENSP00000434594; ENSG00000166548. [O00142-5]
ENST00000527284; ENSP00000435312; ENSG00000166548. [O00142-2]
ENST00000527800; ENSP00000433770; ENSG00000166548. [O00142-5]
ENST00000544898; ENSP00000440898; ENSG00000166548. [O00142-1]
ENST00000545043; ENSP00000438143; ENSG00000166548. [O00142-3]
ENST00000563369; ENSP00000463560; ENSG00000166548. [O00142-5]
ENST00000620035; ENSP00000483833; ENSG00000166548. [O00142-4]
GeneIDi7084.
KEGGihsa:7084.
UCSCiuc002eor.4. human. [O00142-1]

Organism-specific databases

CTDi7084.
DisGeNETi7084.
GeneCardsiTK2.
GeneReviewsiTK2.
H-InvDBHIX0021286.
HGNCiHGNC:11831. TK2.
HPAiHPA041162.
MalaCardsiTK2.
MIMi188250. gene.
609560. phenotype.
neXtProtiNX_O00142.
OpenTargetsiENSG00000166548.
Orphaneti254886. Autosomal recessive progressive external ophthalmoplegia.
254875. Mitochondrial DNA depletion syndrome, myopathic form.
PharmGKBiPA36535.
GenAtlasiSearch...

Phylogenomic databases

eggNOGiKOG4235. Eukaryota.
COG1428. LUCA.
GeneTreeiENSGT00510000046588.
HOGENOMiHOG000006872.
HOVERGENiHBG006216.
InParanoidiO00142.
KOiK00857.
PhylomeDBiO00142.
TreeFamiTF324413.

Enzyme and pathway databases

BioCyciMetaCyc:HS09420-MONOMER.
ZFISH:HS09420-MONOMER.
BRENDAi2.7.1.21. 2681.
ReactomeiR-HSA-113510. E2F mediated regulation of DNA replication.
R-HSA-69205. G1/S-Specific Transcription.
R-HSA-73614. Pyrimidine salvage reactions.
SABIO-RKO00142.

Miscellaneous databases

GenomeRNAii7084.
PROiO00142.
SOURCEiSearch...

Gene expression databases

BgeeiENSG00000166548.
CleanExiHS_TK2.
ExpressionAtlasiO00142. baseline and differential.
GenevisibleiO00142. HS.

Family and domain databases

Gene3Di3.40.50.300. 1 hit.
InterProiIPR002624. DCK/DGK.
IPR031314. DNK_dom.
IPR027417. P-loop_NTPase.
[Graphical view]
PfamiPF01712. dNK. 1 hit.
[Graphical view]
PIRSFiPIRSF000705. DNK. 1 hit.
SUPFAMiSSF52540. SSF52540. 1 hit.
ProtoNetiSearch...

Entry informationi

Entry nameiKITM_HUMAN
AccessioniPrimary (citable) accession number: O00142
Secondary accession number(s): B4DGJ7
, B4DZK7, B7ZAB1, E9PH08, O15238
Entry historyi
Integrated into UniProtKB/Swiss-Prot: November 1, 1997
Last sequence update: July 28, 2009
Last modified: November 2, 2016
This is version 158 of the entry and version 4 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program
DisclaimerAny medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care.

Miscellaneousi

Keywords - Technical termi

Complete proteome, Direct protein sequencing, Reference proteome

Documents

  1. Human chromosome 16
    Human chromosome 16: entries, gene names and cross-references to MIM
  2. Human entries with polymorphisms or disease mutations
    List of human entries with polymorphisms or disease mutations
  3. Human polymorphisms and disease mutations
    Index of human polymorphisms and disease mutations
  4. MIM cross-references
    Online Mendelian Inheritance in Man (MIM) cross-references in UniProtKB/Swiss-Prot
  5. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.