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FLASH GENE
Symbol TK2 contributors: mct/pgu - updated : 10-07-2012
HGNC name thymidine kinase 2, mitochondrial
HGNC id 11831
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