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Ataxia telangiectasia mutated

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Title: Ataxia telangiectasia mutated  
Author: World Heritage Encyclopedia
Language: English
Subject: Ataxia telangiectasia, Ataxia telangiectasia and Rad3 related, P53, DNA repair, Epigenetics
Collection: Ec 2.7.1, Proteins
Publisher: World Heritage Encyclopedia

Ataxia telangiectasia mutated

ATM serine/threonine kinase
Symbols  ; AT1; ATA; ATC; ATD; ATDC; ATE; TEL1; TELO1
External IDs ChEMBL: GeneCards:
EC number
Species Human Mouse
RefSeq (mRNA)
RefSeq (protein)
Location (UCSC)
PubMed search

Ataxia telangiectasia mutated (ATM) is a serine/threonine protein kinase that is recruited and activated by DNA double-strand breaks. It phosphorylates several key proteins that initiate activation of the DNA damage checkpoint, leading to cell cycle arrest, DNA repair or apoptosis. Several of these targets, including p53, CHK2, BRCA1, NBS1 and H2AX are tumor suppressors.

The protein is named for the disorder ataxia telangiectasia caused by mutations of ATM.[1]


  • Introduction 1
  • Structure 2
  • Function 3
  • Regulation 4
  • Role in cancer 5
  • Meiosis 6
  • Interactions 7
  • See also 8
  • References 9
  • Further reading 10
  • External links 11


Throughout the cell cycle the DNA is monitored for damage. Damages result from errors during replication, by-products of metabolism, general toxic drugs or ionizing radiation. The cell cycle has different DNA damage checkpoints, which inhibit the next or maintain the current cell cycle step. There are two main checkpoints, the G1/S and the G2/M, during the cell cycle, which preserve correct progression. ATM plays a role in cell cycle delay after DNA damage, especially after double-strand breaks (DSBs).[2] ATM together with NBS1 act as primary DSB sensor proteins. Different mediators, such as Mre11 and MDC1, acquire post-translational modifications which are generated by the sensor proteins. These modified mediator proteins then amplify the DNA damage signal, and transduce the signals to downstream effectors such as CHK2 and p53.


The ATM gene codes for a 350 kDa protein consisting of 3056 amino acids.[3] ATM belongs to the superfamily of phosphatidylinositol 3-kinase-related kinases (PIKKs). The PIKK superfamily comprises six Ser/Thr-protein kinases that show a sequence similarity to phosphatidylinositol 3-kinases (PI3Ks). This protein kinase family includes amongst others ATR (ATM- and RAD3-related), DNA-PKcs (DNA-dependent protein kinase catalytic subunit) and mTOR (mammalian target of rapamycin). Characteristic for ATM are five domains. These are from N-Terminus to C-Terminus the HEAT repeat domain, the FRAP-ATM-TRRAP (FAT) domain, the kinase domain (KD), the PIKK-regulatory domain (PRD) and the FAT-C-terminal (FATC) domain. The HEAT repeats directly bind to the C-terminus of NBS1. The FAT domain interacts with ATM's kinase domain to stabilize the C-terminus region of ATM itself. The KD domain resumes kinase activity, while the PRD and the FATC domain regulate it. Although no structure for ATM has been solved, the overall shape of ATM is very similar to DNA-PKcs and is composed of a head and a long arm that is thought to wrap around double-stranded DNA after a conformational change. The entire N-terminal domain together with the FAT domain are predicted to adopt an α-helical structure, which was found by sequence analysis. This α-helical structure is believed to form a tertiary structure, which has a curved, tubular shape present for example in the Huntingtin protein, which also contains HEAT repeats. FATC is the C-terminal domain with a length of about 30 amino acids. It is highly conserved and consists of an α-helix followed by a sharp turn, which is stabilized by a disulfide bond.[4]

Schematic illustration of the four known conserved domains in four members of the PIKKs family.[4]


A complex of the three proteins [7]

ATM-mediated two-step response to DNA double strand breaks. In the rapid response activated ATM phosphorylates effector kinase CHK2 which phophphorylates CDC25A, targeting it for ubiquitination and degradation. Therefore phosphorylated CDK2-Cyclin accumulates and progression through the cell cycle is blocked. In the delayed response ATM phosphorylates the inhibitor of p53, MDM2, and p53, which is also phosphorylated by Chk2. The resulting activation and stabilization of p53 leads to an increased expression of Cdk inhibitor p21, which further helps to keep Cdk activity low and to maintain long-term cell cycle arrest.[7]

The protein kinase ATM may also be involved in mitochondrial homeostasis, as a regulator of mitochondrial autophagy (mitophagy) whereby old, dysfunctional mitochondria are removed.[8]


A functional MRN complex is required for ATM activation after double strand breaks (DSBs). The complex functions upstream of ATM in mammalian cells and induces conformational changes that facilitate an increase in the affinity of ATM towards its substrates, such as CHK2 and p53.[2] Inactive ATM is present in the cells without DSBs as dimers or multimers. Upon DNA damage, ATM autophosphorylates on residue Ser1981. This phosphorylation provokes dissociation of ATM dimers, which is followed by the release of active ATM monomers.[9] Further autophosphorylation (of residues Ser367 and Ser1893) is required for normal activity of the ATM kinase. Activation of ATM by the MRN complex is preceded by at least two steps, i.e. recruitment of ATM to DSB ends by the mediator of DNA damage checkpoint protein 1 (MDC1) which binds to MRE11, and the subsequent stimulation of kinase activity with the NBS1 C-terminus. The three domains FAT, PRD and FATC are all involved in regulating the activity of the KD kinase domain. The FAT domain interacts with ATM's KD domain to stabilize the C-terminus region of ATM itself. The FATC domain is critical for kinase activity and highly sensitive to mutagenesis. It mediates protein-protein interaction for example with the histone acetyltransferase TIP60 (HIV-1 Tat interacting protein 60 kDa), which acetylates ATM on residue Lys3016. The acetylation occurs in the C-terminal half of the PRD domain and is required for ATM kinase activation and for its conversion into monomers. While deletion of the entire PRD domain abolishes the kinase activity of ATM, specific small deletions show no effect.[4]

Role in cancer

Ataxia telangiectasia (AT) is a rare human disease characterized by cerebellar degeneration, extreme cellular sensitivity to radiation and a predisposition to cancer. All AT patients contain mutations in the ATM gene (ATM). Most other AT-like disorders are defective in genes encoding the MRN protein complex. One feature of the ATM protein is its rapid increase in kinase activity immediately following double-strand break formation.[10][11] The phenotypic manifestation of AT is due to the broad range of substrates for the ATM kinase, involving DNA repair, apoptosis, G1/S, intra-S checkpoint and G2/M checkpoints, gene regulation, translation initiation, and telomere maintenance.[12] Therefore a defect in ATM has severe consequences in repairing certain types of damage to DNA, and cancer may result from improper repair. AT patients have an increased risk for breast cancer that has been ascribed to ATM's interaction and phosphorylation of BRCA1 and its associated proteins following DNA damage.[13] Certain kinds of leukemias and lymphomas, including Mantle cell lymphoma, T-ALL, atypical B cell chronic lymphocytic leukemia, and T-PLL are also associated with ATM defects.[14]


ATM functions during meiotic prophase.[15] The wild-type ATM gene is expressed at a 4-fold increased level in human testes compared to somatic cells (such as skin fibroblasts).[16] In both mice and humans, ATM deficiency results in female and male infertility. Deficient ATM expression causes severe meiotic disruption during prophase I.[17] In addition, impaired ATM-mediated DNA double-strand break (DSB) repair has been identified as a likely cause of aging of mouse and human oocytes.[18] Expression of the ATM gene, as well as other key DSB repair genes, declines with age in mouse and human oocytes and this decline is paralleled by an increase of DSBs in primordial follicles.[18] These findings indicate that ATM-mediated homologous recombinational repair is a crucial function of meiosis.


Ataxia telangiectasia mutated has been shown to interact with:

See also


  1. ^ "Entrez Gene: ATM ataxia telangiectasia mutated (includes complementation groups A, C and D)". 
  2. ^ a b Lee JH, Paull TT (December 2007). "Activation and regulation of ATM kinase activity in response to DNA double-strand breaks". Oncogene 26 (56): 7741–8.  
  3. ^ "Serine-protein kinase ATM - Homo sapiens (Human)". 
  4. ^ a b c Lempiäinen H, Halazonetis TD (October 2009). "Emerging common themes in regulation of PIKKs and PI3Ks". EMBO J. 28 (20): 3067–73.  
  5. ^ Huang X, Halicka HD, Darzynkiewicz Z (November 2004). "Detection of histone H2AX phosphorylation on Ser-139 as an indicator of DNA damage (DNA double-strand breaks)". Curr Protoc Cytom. Chapter 7: Unit 7.27.  
  6. ^ Canman CE, Lim DS, Cimprich KA, Taya Y, Tamai K, Sakaguchi K, Appella E, Kastan MB, Siliciano JD (September 1998). "Activation of the ATM kinase by ionizing radiation and phosphorylation of p53". Science 281 (5383): 1677–9.  
  7. ^ a b Morgan, David O. (2007).  
  8. ^ Valentin-Vega YA, Maclean KH, Tait-Mulder J, Milasta S, Steeves M, Dorsey FC, Cleveland JL, Green DR, Kastan MB (2012). "Mitochondrial dysfunction in ataxia-telangiectasia". Blood 119 (6): 1490–500.  
  9. ^ Bakkenist CJ, Kastan MB (January 2003). "DNA damage activates ATM through intermolecular autophosphorylation and dimer dissociation". Nature 421 (6922): 499–506.  
  10. ^ Canman CE, Lim DS (December 1998). "The role of ATM in DNA damage responses and cancer". Oncogene 17 (25): 3301–8.  
  11. ^ Banin S, Moyal L, Shieh S, Taya Y, Anderson CW, Chessa L, Smorodinsky NI, Prives C, Reiss Y, Shiloh Y, Ziv Y (September 1998). "Enhanced phosphorylation of p53 by ATM in response to DNA damage". Science 281 (5383): 1674–7.  
  12. ^ Kurz EU, Lees-Miller SP (2004). "DNA damage-induced activation of ATM and ATM-dependent signaling pathways". DNA Repair (Amst.) 3 (8–9): 889–900.  
  13. ^ a b Chen J (September 2000). "Ataxia telangiectasia-related protein is involved in the phosphorylation of BRCA1 following deoxyribonucleic acid damage". Cancer Res. 60 (18): 5037–9.  
  14. ^ Friedenson B (2007). "The BRCA1/2 pathway prevents hematologic cancers in addition to breast and ovarian cancers". BMC Cancer 7: 152.  
  15. ^ Hamer G, Kal HB, Westphal CH, Ashley T, de Rooij DG (2004). "Ataxia telangiectasia mutated expression and activation in the testis". Biol. Reprod. 70 (4): 1206–12.  
  16. ^ Galetzka D, Weis E, Kohlschmidt N, Bitz O, Stein R, Haaf T (2007). "Expression of somatic DNA repair genes in human testes". J. Cell. Biochem. 100 (5): 1232–9.  
  17. ^ Barlow C, Liyanage M, Moens PB, Tarsounas M, Nagashima K, Brown K, Rottinghaus S, Jackson SP, Tagle D, Ried T, Wynshaw-Boris A (1998). "Atm deficiency results in severe meiotic disruption as early as leptonema of prophase I". Development 125 (20): 4007–17.  
  18. ^ a b Titus S, Li F, Stobezki R, Akula K, Unsal E, Jeong K, Dickler M, Robson M, Moy F, Goswami S, Oktay K (2013). "Impairment of BRCA1-related DNA double-strand break repair leads to ovarian aging in mice and humans". Sci Transl Med 5 (172): 172ra21.  
  19. ^ a b Chen G, Yuan SS, Liu W, Xu Y, Trujillo K, Song B, Cong F, Goff SP, Wu Y, Arlinghaus R, Baltimore D, Gasser PJ, Park MS, Sung P, Lee EY (April 1999). "Radiation-induced assembly of Rad51 and Rad52 recombination complex requires ATM and c-Abl". J. Biol. Chem. 274 (18): 12748–52.  
  20. ^ a b Kishi S, Zhou XZ, Ziv Y, Khoo C, Hill DE, Shiloh Y, Lu KP (August 2001). "Telomeric protein Pin2/TRF1 as an important ATM target in response to double strand DNA breaks". J. Biol. Chem. 276 (31): 29282–91.  
  21. ^ Shafman T, Khanna KK, Kedar P, Spring K, Kozlov S, Yen T, Hobson K, Gatei M, Zhang N, Watters D, Egerton M, Shiloh Y, Kharbanda S, Kufe D, Lavin MF (May 1997). "Interaction between ATM protein and c-Abl in response to DNA damage". Nature 387 (6632): 520–3.  
  22. ^ a b c d e f g Kim ST, Lim DS, Canman CE, Kastan MB (Dec 1999). "Substrate specificities and identification of putative substrates of ATM kinase family members". J. Biol. Chem. 274 (53): 37538–43.  
  23. ^ a b c d Wang Y, Cortez D, Yazdi P, Neff N, Elledge SJ, Qin J (April 2000). "BASC, a super complex of BRCA1-associated proteins involved in the recognition and repair of aberrant DNA structures". Genes Dev. 14 (8): 927–39.  
  24. ^ Gatei M, Scott SP, Filippovitch I, Soronika N, Lavin MF, Weber B, Khanna KK (June 2000). "Role for ATM in DNA damage-induced phosphorylation of BRCA1". Cancer Res. 60 (12): 3299–304.  
  25. ^ Cortez D, Wang Y, Qin J, Elledge SJ (November 1999). "Requirement of ATM-dependent phosphorylation of brca1 in the DNA damage response to double-strand breaks". Science 286 (5442): 1162–6.  
  26. ^ Tibbetts RS, Cortez D, Brumbaugh KM, Scully R, Livingston D, Elledge SJ, Abraham RT (Dec 2000). "Functional interactions between BRCA1 and the checkpoint kinase ATR during genotoxic stress". Genes Dev. 14 (23): 2989–3002.  
  27. ^ Gatei M, Zhou BB, Hobson K, Scott S, Young D, Khanna KK (May 2001). "Ataxia telangiectasia mutated (ATM) kinase and ATM and Rad3 related kinase mediate phosphorylation of Brca1 at distinct and overlapping sites. In vivo assessment using phospho-specific antibodies". J. Biol. Chem. 276 (20): 17276–80.  
  28. ^ Beamish H, Kedar P, Kaneko H, Chen P, Fukao T, Peng C, Beresten S, Gueven N, Purdie D, Lees-Miller S, Ellis N, Kondo N, Lavin MF (August 2002). "Functional link between BLM defective in Bloom's syndrome and the ataxia-telangiectasia-mutated protein, ATM". J. Biol. Chem. 277 (34): 30515–23.  
  29. ^ Suzuki K, Kodama S, Watanabe M (September 1999). "Recruitment of ATM protein to double strand DNA irradiated with ionizing radiation". J. Biol. Chem. 274 (36): 25571–5.  
  30. ^ Taniguchi T, Garcia-Higuera I, Xu B, Andreassen PR, Gregory RC, Kim ST, Lane WS, Kastan MB, D'Andrea AD (May 2002). "Convergence of the fanconi anemia and ataxia telangiectasia signaling pathways". Cell 109 (4): 459–72.  
  31. ^ Reuter TY, Medhurst AL, Waisfisz Q, Zhi Y, Herterich S, Hoehn H, Gross HJ, Joenje H, Hoatlin ME, Mathew CG, Huber PA (October 2003). "Yeast two-hybrid screens imply involvement of Fanconi anemia proteins in transcription regulation, cell signaling, oxidative metabolism, and cellular transport". Exp. Cell Res. 289 (2): 211–21.  
  32. ^ Kang J, Ferguson D, Song H, Bassing C, Eckersdorff M, Alt FW, Xu Y (January 2005). "Functional interaction of H2AX, NBS1, and p53 in ATM-dependent DNA damage responses and tumor suppression". Mol. Cell. Biol. 25 (2): 661–70.  
  33. ^ Fabbro M, Savage K, Hobson K, Deans AJ, Powell SN, McArthur GA, Khanna KK (July 2004). "BRCA1-BARD1 complexes are required for p53Ser-15 phosphorylation and a G1/S arrest following ionizing radiation-induced DNA damage". J. Biol. Chem. 279 (30): 31251–8.  
  34. ^ Khanna KK, Keating KE, Kozlov S, Scott S, Gatei M, Hobson K, Taya Y, Gabrielli B, Chan D, Lees-Miller SP, Lavin MF (Dec 1998). "ATM associates with and phosphorylates p53: mapping the region of interaction". Nat. Genet. 20 (4): 398–400.  
  35. ^ Westphal CH, Schmaltz C, Rowan S, Elson A, Fisher DE, Leder P (May 1997). "Genetic interactions between atm and p53 influence cellular proliferation and irradiation-induced cell cycle checkpoints". Cancer Res. 57 (9): 1664–7.  
  36. ^ Bao S, Tibbetts RS, Brumbaugh KM, Fang Y, Richardson DA, Ali A, Chen SM, Abraham RT, Wang XF (June 2001). "ATR/ATM-mediated phosphorylation of human Rad17 is required for genotoxic stress responses". Nature 411 (6840): 969–74.  
  37. ^ Li S, Ting NS, Zheng L, Chen PL, Ziv Y, Shiloh Y, Lee EY, Lee WH (July 2000). "Functional link of BRCA1 and ataxia telangiectasia gene product in DNA damage response". Nature 406 (6792): 210–5.  
  38. ^ Long X, Lin Y, Ortiz-Vega S, Yonezawa K, Avruch J (April 2005). "Rheb binds and regulates the mTOR kinase". Curr. Biol. 15 (8): 702–13.  
  39. ^ Chang L, Zhou B, Hu S, Guo R, Liu X, Jones SN, Yen Y (November 2008). "ATM-mediated serine 72 phosphorylation stabilizes ribonucleotide reductase small subunit p53R2 protein against MDM2 to DNA damage". Proc. Natl. Acad. Sci. U.S.A. 105 (47): 18519–24.  
  40. ^ Kim ST, Xu B, Kastan MB (March 2002). "Involvement of the cohesin protein, Smc1, in Atm-dependent and independent responses to DNA damage". Genes Dev. 16 (5): 560–70.  
  41. ^ Fernandez-Capetillo O, Chen HT, Celeste A, Ward I, Romanienko PJ, Morales JC, Naka K, Xia Z, Camerini-Otero RD, Motoyama N, Carpenter PB, Bonner WM, Chen J, Nussenzweig A (Dec 2002). "DNA damage-induced G2-M checkpoint activation by histone H2AX and 53BP1". Nat. Cell Biol. 4 (12): 993–7.  
  42. ^ Ward IM, Minn K, Jorda KG, Chen J (May 2003). "Accumulation of checkpoint protein 53BP1 at DNA breaks involves its binding to phosphorylated histone H2AX". J. Biol. Chem. 278 (22): 19579–82.  

Further reading

  • Giaccia AJ, Kastan MB (1998). "The complexity of p53 modulation: emerging patterns from divergent signals". Genes Dev. 12 (19): 2973–83.  
  • Kastan MB, Lim DS (2001). "The many substrates and functions of ATM". Nature Reviews Molecular Cell Biology 1 (3): 179–86.  
  • Shiloh Y (2002). "ATM: from phenotype to functional genomics--and back". Ernst Schering Res. Found. Workshop (36): 51–70.  
  • Redon C, Pilch D, Rogakou E, Sedelnikova O, Newrock K, Bonner W (2002). "Histone H2A variants H2AX and H2AZ". Current Opinion in Genetics & Development 12 (2): 162–9.  
  • Tang Y (2003). "[ATM and Cancer]". Zhongguo Shi Yan Xue Ye Xue Za Zhi 10 (1): 77–80.  
  • Shiloh Y (2003). "ATM and related protein kinases: safeguarding genome integrity". Nature Reviews Cancer 3 (3): 155–68.  
  • Gumy-Pause F, Wacker P, Sappino AP (2004). "ATM gene and lymphoid malignancies". Leukemia 18 (2): 238–42.  
  • Kurz EU, Lees-Miller SP (2005). "DNA damage-induced activation of ATM and ATM-dependent signaling pathways". DNA Repair (Amst.) 3 (8–9): 889–900.  
  • Abraham RT (2005). "The ATM-related kinase, hSMG-1, bridges genome and RNA surveillance pathways". DNA Repair (Amst.) 3 (8–9): 919–25.  
  • Lavin MF, Scott S, Gueven N, Kozlov S, Peng C, Chen P (2005). "Functional consequences of sequence alterations in the ATM gene". DNA Repair (Amst.) 3 (8–9): 1197–205.  
  • Meulmeester E, Pereg Y, Shiloh Y, Jochemsen AG (2006). "ATM-mediated phosphorylations inhibit Mdmx/Mdm2 stabilization by HAUSP in favor of p53 activation". Cell Cycle 4 (9): 1166–70.  
  • Ahmed M, Rahman N (2006). "ATM and breast cancer susceptibility". Oncogene 25 (43): 5906–11.  

External links

  • - The Interactive Flytelomere fusion Drosophila
  • GeneReviews/NCBI/NIH/UW entry on Ataxia telangiectasia
  • OMIM entries on Ataxia telangiectasia
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