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TK2 thymidine kinase 2 [ Homo sapiens (human) ]

Gene ID: 7084, updated on 1-Jun-2020

Summary

Official Symbol
TK2provided by HGNC
Official Full Name
thymidine kinase 2provided by HGNC
Primary source
HGNC:HGNC:11831
See related
Ensembl:ENSG00000166548 MIM:188250
Gene type
protein coding
RefSeq status
REVIEWED
Organism
Homo sapiens
Lineage
Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo
Also known as
MTTK; PEOB3; SCA31; MTDPS2
Summary
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]
Expression
Ubiquitous expression in fat (RPKM 14.4), testis (RPKM 9.6) and 25 other tissues See more
Orthologs

Genomic context

See TK2 in Genome Data Viewer
Location:
16q21
Exon count:
11
Annotation release Status Assembly Chr Location
109.20200522 current GRCh38.p13 (GCF_000001405.39) 16 NC_000016.10 (66508003..66550412, complement)
105 previous assembly GRCh37.p13 (GCF_000001405.25) 16 NC_000016.9 (66541906..66584315, complement)

Chromosome 16 - NC_000016.10Genomic Context describing neighboring genes Neighboring gene brain expressed associated with NEDD4 1 Neighboring gene nuclear envelope phosphatase-regulatory subunit 1 pseudogene Neighboring gene BEAN1 antisense RNA 1 Neighboring gene CKLF-CMTM1 readthrough Neighboring gene chemokine like factor Neighboring gene CKLF like MARVEL transmembrane domain containing 1

Genomic regions, transcripts, and products

Expression

  • Project title: HPA RNA-seq normal tissues
  • Description: RNA-seq was performed of tissue samples from 95 human individuals representing 27 different tissues in order to determine tissue-specificity of all protein-coding genes
  • BioProject: PRJEB4337
  • Publication: PMID 24309898
  • Analysis date: Wed Apr 4 07:08:55 2018

Bibliography

GeneRIFs: Gene References Into Functions

What's a GeneRIF?

Pathways from PubChem

Interactions

Products Interactant Other Gene Complex Source Pubs Description

General gene information

Markers

Homology

Gene Ontology Provided by GOA

Function Evidence Code Pubs
ATP binding IEA
Inferred from Electronic Annotation
more info
 
deoxycytidine kinase activity IEA
Inferred from Electronic Annotation
more info
 
deoxynucleoside kinase activity IBA
Inferred from Biological aspect of Ancestor
more info
PubMed 
nucleoside kinase activity TAS
Traceable Author Statement
more info
 
thymidine kinase activity IEA
Inferred from Electronic Annotation
more info
 
Process Evidence Code Pubs
DNA biosynthetic process IEA
Inferred from Electronic Annotation
more info
 
deoxycytidine metabolic process IEA
Inferred from Electronic Annotation
more info
 
deoxyribonucleoside monophosphate biosynthetic process IEA
Inferred from Electronic Annotation
more info
 
nucleobase-containing compound metabolic process TAS
Traceable Author Statement
more info
PubMed 
nucleotide biosynthetic process IEA
Inferred from Electronic Annotation
more info
 
phosphorylation IEA
Inferred from Electronic Annotation
more info
 
pyrimidine nucleoside salvage TAS
Traceable Author Statement
more info
 
thymidine metabolic process IEA
Inferred from Electronic Annotation
more info
 
Component Evidence Code Pubs
cytoplasm IBA
Inferred from Biological aspect of Ancestor
more info
PubMed 
mitochondrial matrix TAS
Traceable Author Statement
more info
 
mitochondrion IBA
Inferred from Biological aspect of Ancestor
more info
PubMed 

General protein information

Preferred Names
thymidine kinase 2, mitochondrial; thymidine kinase 2
Names
mitochondrial thymidine kinase
mt-TK
NP_001166114.1
NP_001166115.1
NP_001166116.1
NP_001258863.1
NP_001258864.1
NP_001258979.1
NP_004605.4

NCBI Reference Sequences (RefSeq)

RefSeqs maintained independently of Annotated Genomes

These reference sequences exist independently of genome builds. Explain

These reference sequences are curated independently of the genome annotation cycle, so their versions may not match the RefSeq versions in the current genome build. Identify version mismatches by comparing the version of the RefSeq in this section to the one reported in Genomic regions, transcripts, and products above.

Genomic

  1. NG_016862.1 RefSeqGene

    Range
    5291..47410
    Download
    GenBank, FASTA, Sequence Viewer (Graphics)

mRNA and Protein(s)

  1. NM_001172643.1NP_001166114.1  thymidine kinase 2 isoform 2

    See identical proteins and their annotated locations for NP_001166114.1

    Status: REVIEWED

    Description
    Transcript Variant: This variant (2) differs in the 5' UTR, lacks a portion of the 5' coding region, and initiates translation at an alternate start codon, compared to variant 1. The encoded isoform (2) is not localized to mitochondria, and it has a distinct N-terminus and is shorter than isoform 1.
    Source sequence(s)
    AC010542, U77088
    Consensus CDS
    CCDS54018.1
    UniProtKB/Swiss-Prot
    O00142
    Related
    ENSP00000435312.1, ENST00000527284.5
    Conserved Domains (2) summary
    TIGR00041
    Location:22207
    DTMP_kinase; dTMP kinase
    pfam01712
    Location:22234
    dNK; Deoxynucleoside kinase
  2. NM_001172644.2NP_001166115.1  thymidine kinase 2, mitochondrial isoform 3 precursor

    See identical proteins and their annotated locations for NP_001166115.1

    Status: REVIEWED

    Description
    Transcript Variant: This variant (3) lacks an in-frame exon in the coding region, compared to variant 1. The encoded isoform (3) is shorter than isoform 1.
    Source sequence(s)
    AC010542, AF521891, AK295808
    Consensus CDS
    CCDS54016.1
    UniProtKB/Swiss-Prot
    O00142
    UniProtKB/TrEMBL
    B4DIW4, Q8IZR3
    Related
    ENSP00000438143.2, ENST00000545043.6
    Conserved Domains (1) summary
    pfam01712
    Location:52240
    dNK; Deoxynucleoside kinase
  3. NM_001172645.1NP_001166116.1  thymidine kinase 2, mitochondrial isoform 4 precursor

    Status: REVIEWED

    Description
    Transcript Variant: This variant (4) lacks an in-frame exon in the coding region, compared to variant 1. The encoded isoform (4) is shorter than isoform 1.
    Source sequence(s)
    AC010542, AF521891, AK303590
    Consensus CDS
    CCDS54017.1
    UniProtKB/TrEMBL
    B4E0Z4, Q8IZR3
    Related
    ENSP00000483833.1, ENST00000620035.4
    Conserved Domains (2) summary
    TIGR00041
    Location:53220
    DTMP_kinase; dTMP kinase
    pfam01712
    Location:53247
    dNK; Deoxynucleoside kinase
  4. NM_001271934.2NP_001258863.1  thymidine kinase 2 isoform 5

    Status: REVIEWED

    Description
    Transcript Variant: This variant (5) has an additional exon in the 5' region, which results in an alternate translation start codon, compared to variant 1. The encoded isoform (5) is not localized to mitochondria, and it has a distinct N-terminus and is shorter than isoform 1.
    Source sequence(s)
    AC010542, AF521891, AK303590, AL038860, BC142970
    UniProtKB/TrEMBL
    A5PLM0, B4E0Z4, Q8IZR3
    Conserved Domains (2) summary
    TIGR00041
    Location:4189
    DTMP_kinase; dTMP kinase
    pfam01712
    Location:4211
    dNK; Deoxynucleoside kinase
  5. NM_001271935.1NP_001258864.1  thymidine kinase 2 isoform 6

    Status: REVIEWED

    Description
    Transcript Variant: This variant (6) differs in the 5' UTR, lacks a portion of the 5' coding region and two internal exons, and initiates translation at an alternate start codon, compared to variant 1. The encoded isoform (6) is not localized to mitochondria, and it has a distinct N-terminus, lacks an internal segment and is shorter than isoform 1.
    Source sequence(s)
    AC010542, AL038860, BC113928, BC134344, U77088
    UniProtKB/Swiss-Prot
    O00142
    UniProtKB/TrEMBL
    A4IF54
    Related
    ENSP00000464313.1, ENST00000569718.5
    Conserved Domains (1) summary
    cl17190
    Location:22121
    NK; Nucleoside/nucleotide kinase (NK) is a protein superfamily consisting of multiple families of enzymes that share structural similarity and are functionally related to the catalysis of the reversible phosphate group transfer from nucleoside triphosphates ...
  6. NM_001272050.2NP_001258979.1  thymidine kinase 2, mitochondrial isoform 7 precursor

    See identical proteins and their annotated locations for NP_001258979.1

    Status: REVIEWED

    Description
    Transcript Variant: This variant (9) contains an alternate 5' exon and initiates translation at a downstream start codon, compared to variant 1. The encoded isoform (7) has a shorter N-terminus, compared to isoform 1, but is predicted to be a mitochondrial protein.
    Source sequence(s)
    AC010542, AK302976, AL038860, BC134344
    Consensus CDS
    CCDS61955.1
    UniProtKB/Swiss-Prot
    O00142
    UniProtKB/TrEMBL
    A4IF54
    Related
    ENSP00000434594.1, ENST00000525974.5
    Conserved Domains (1) summary
    cl17190
    Location:1163
    NK; Nucleoside/nucleotide kinase (NK) is a protein superfamily consisting of multiple families of enzymes that share structural similarity and are functionally related to the catalysis of the reversible phosphate group transfer from nucleoside triphosphates ...
  7. NM_004614.5NP_004605.4  thymidine kinase 2, mitochondrial isoform 1 precursor

    See identical proteins and their annotated locations for NP_004605.4

    Status: REVIEWED

    Description
    Transcript Variant: This variant (1) represents the longest transcript and encodes the longest isoform (1).
    Source sequence(s)
    AC010542, AF521891
    Consensus CDS
    CCDS10805.2
    UniProtKB/Swiss-Prot
    O00142
    UniProtKB/TrEMBL
    Q8IZR3
    Related
    ENSP00000440898.2, ENST00000544898.6
    Conserved Domains (2) summary
    TIGR00041
    Location:53238
    DTMP_kinase; dTMP kinase
    pfam01712
    Location:53265
    dNK; Deoxynucleoside kinase

RNA

  1. NR_073520.2 RNA Sequence

    Status: REVIEWED

    Description
    Transcript Variant: This variant (7) lacks a splice junction in the 5' region, which is supported by several transcripts, compared to variant 1. This variant is represented as non-coding because the use of the 5'-most supported translational start codon, as used in variant 1, renders the transcript a candidate for nonsense-mediated mRNA decay (NMD).
    Source sequence(s)
    AC010542, AL038860, BC134344, U80628

RefSeqs of Annotated Genomes: Homo sapiens Updated Annotation Release 109.

The following sections contain reference sequences that belong to a specific genome build. Explain

Reference GRCh38.p13 Primary Assembly

Genomic

  1. NC_000016.10 Reference GRCh38.p13 Primary Assembly

    Range
    66508003..66550412 complement
    Download
    GenBank, FASTA, Sequence Viewer (Graphics)

Suppressed Reference Sequence(s)

The following Reference Sequences have been suppressed. Explain

  1. NR_073521.1: Suppressed sequence

    Description
    NR_073521.1: This RefSeq was permanently suppressed because it is now thought that this gene does encode a protein.
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