Adenylate kinase 2 is an enzyme that is encoded in humans by the AK2gene.[5][6][7] The AK2 protein is found in the intermembrane space of the mitochondrion.[8][9]
Function
Adenylate kinases are involved in regulating the adenine nucleotide composition within a cell by catalyzing the reversible transfer of phosphate groups among adenine nucleotides. Three isozymes of adenylate kinase, namely 1, 2, and 3, have been identified in vertebrates; this gene encodes isozyme 2. Expression of these isozymes is tissue-specific and developmentally regulated. Isozyme 2 is localized in the mitochondrial intermembrane space and may play a role in apoptosis. Two transcript variants encoding distinct isoforms have been identified for this gene.[7]
AK2 deficiency
Adenylate Kinase 2 (AK2) deficiency in humans causes hematopoietic defects associated with sensorineural deafness.[10][11] Recticular dysgenesis is an autosomal recessive form of human combined immunodeficiency. It is also characterized by an impaired lymphoid maturation and early differentiation arrest in the myeloid lineage. AK2 deficiency results in absent or a large decrease in the expression of proteins. AK2 is specifically expressed in the stria vascularis of the inner ear which indicates why individuals with an AK2 deficiency will have sensorineural deafness.[11]
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Lee Y, Kim JW, Lee IA, Kang HB, Choe YK, Lee HG, Lim JS, Kim HJ, Park C, Choe IS (Feb 1997). "Cloning and characterization of cDNA for human adenylate kinase 2A". Biochem Mol Biol Int. 39 (4): 833–42. PMID8843353.
^Carritt B, King J, Welch HM (Mar 1983). "Gene order and localization of enzyme loci on the short arm of chromosome 1". Ann Hum Genet. 46 (Pt 4): 329–35. doi:10.1111/j.1469-1809.1982.tb01583.x. PMID6961883.
^Bruns GA, Regina VM (1977). "Adenylate kinase 2, a mitochondrial enzyme". Biochem. Genet. 15 (5–6): 477–86. doi:10.1007/BF00520192. PMID195572.
^Köhler C, Gahm A, Noma T, et al. (1999). "Release of adenylate kinase 2 from the mitochondrial intermembrane space during apoptosis". FEBS Lett. 447 (1): 10–2. doi:10.1016/S0014-5793(99)00251-3. PMID10218571.
^Pannicke U, Hönig M, Hess I, et al. (January 2009). "Reticular dysgenesis (aleukocytosis) is caused by mutations in the gene encoding mitochondrial adenylate kinase 2". Nat. Genet. 41 (1): 101–105. doi:10.1038/ng.265. PMID19043417.
Lee Y, Kim JW, Lee SM, et al. (1998). "Cloning and expression of human adenylate kinase 2 isozymes: differential expression of adenylate kinase 1 and 2 in human muscle tissues". J. Biochem. 123 (1): 47–54. doi:10.1093/oxfordjournals.jbchem.a021915. PMID9504408.
Noma T, Song S, Yoon YS, et al. (1998). "cDNA cloning and tissue-specific expression of the gene encoding human adenylate kinase isozyme 2". Biochim. Biophys. Acta. 1395 (1): 34–9. doi:10.1016/s0167-4781(97)00193-0. PMID9434148.
Hamada M, Sumida M, Okuda H, et al. (1982). "Adenosine triphosphate-adenosine-5'-monophosphate phosphotransferase from normal human liver mitochondria. Isolation, chemical properties, and immunochemical comparison with Duchenne dystrophic serum aberrant adenylate kinase". J. Biol. Chem. 257 (21): 13120–8. PMID6182143.
