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FLASH GENE
Symbol TK2 contributors: mct/pgu - updated : 10-07-2012
HGNC name thymidine kinase 2, mitochondrial
HGNC id 11831
Corresponding disease
MDDS2 mitochondrial DNA depletion syndrome, myopathic form
Location 16q21      Physical location : 66.541.906 - 66.584.315
Synonym symbol(s) MTDPS2, MTTK
EC.number 2.7.1.21
DNA
TYPE locus Control Region
STRUCTURE 42.41 kb     10 Exon(s)
10 Kb 5' upstream gene genomic sequence study
regulatory sequence Promoter
text structure Y-box sequence 5' - CTGATTGG - 3' in cis-regulatory elements
MAPPING cloned Y linked N status confirmed
RNA
TRANSCRIPTS type messenger
identificationnb exonstypebpproduct
ProteinkDaAAspecific expressionYearPubmed
10 - 5114 - 265 - 2007 17468435
- - - - - successfully expressed in the cytoplasm of transduced cells 2007 17468435
  • truncated at the N terminus
    • 9 - 5039 28 240 - 2007 17468435
    9 - 5060 - 247 - 2007 17468435
    EXPRESSION
    Type
       expressed in (based on citations)
    organ(s)
    SystemOrgan level 1Organ level 2Organ level 3Organ level 4LevelPubmedSpeciesStageRna symbol
    Cardiovascularheart    
    Digestiveliver    
    Endocrinepancreas    
    Nervousbrain    
    Urinarykidney    
    tissue
    SystemTissueTissue level 1Tissue level 2LevelPubmedSpeciesStageRna symbol
    Epithelialsecretoryglandularendocrine 
    Epithelialsecretoryglandularexocrine 
    Muscularstriatumskeletal  
    cell lineage
    cell lines
    fluid/secretion
    at STAGE
    physiological period fetal
    Text eye
    PROTEIN
    PHYSICAL PROPERTIES
    STRUCTURE
    motifs/domains
    mono polymer monomer
    HOMOLOGY
    Homologene
    FAMILY DCK//DGK family
    CATEGORY enzyme
    SUBCELLULAR LOCALIZATION     intracellular
    intracellular,cytoplasm,organelle,mitochondria,matrix
    basic FUNCTION
  • involved in the activation of chemotherapeutic nucleoside analogues
  • catalyzes the phosphorylation of thymidine in mitochondria, and its function becomes essential for thymidine triphosphate pools synthesis in noncycling cells
  • phosphorylating thymidine, deoxycytidine, and deoxyuridine
  • essential component of the mitochondrial nucleotide salvage pathway, the main source of nucleotides for mtDNA synthesis and maintenance in postmitotic cells
  • blood cells are less dependent on mitochondrial TK2 compared with several other tissues and these cells can synthesize deoxyribonucleotides required for mtDNA replication by alternative pathways such as phosphorylation of thymidine by cytosolic TK1
  • constitutively expressed in the mitochondria and playing an important role for the replication and maintenance of mitochondrial DNA (mtDNA)
  • phosphorylates thymidine and deoxycytidine and is essential for mitochondrial function
  • is sensitive to the cellular/mitochondrial redox status, and this redox regulation of the TK2 protein may play an important role in mitochondrial DNA replication and maintenance
    • CELLULAR PROCESS
    PHYSIOLOGICAL PROCESS
    PATHWAY
    metabolism
    signaling
    a component
  • essential component of the mitochondrial nucleotide salvage pathway
    • INTERACTION
    DNA
    RNA
    small molecule
    protein
    cell & other
    REGULATION
    Other its activity can be modulated by reducing or oxidizing agents and such modifications lead to large variations of the activity (PMIDl:
    ASSOCIATED DISORDERS
    corresponding disease(s) MDDS2
    related resource MITOP database
    Other morbid association(s)
    TypeGene ModificationChromosome rearrangementProtein expressionProtein Function
    constitutional     --low  
    results in neuronal dysfunction
    constitutional     --low  
    impairment of TK2 expression leads to profound mtDNA depletion but fully preserved or even enhanced mitochondrial respiratory activity
    Susceptibility
    Variant & Polymorphism
    Candidate gene
    Marker
    Therapy target
    ANIMAL & CELL MODELS
  • after 10
    • -12 days of life the TK2-/- mice display an ataxic phenotype with severely impaired motor coordination and gait, and abnormal limb-clasping reflexes
  • altered mitochondrial morphology in brown but not in white adipocytes from TK2-deficient mice
  • MtDNA levels in spleen from the Tk2-deficient mice were decreased 50p100, but in contrast to all other investigated organs, both thymus and peripheral blood leukocytes showed normal mtDNA levels