Cyclin-A2 is a protein that in humans is encoded by the CCNA2 gene.[5] It is one of the two types of cyclin A: cyclin A1 is expressed during meiosis and embryogenesis while cyclin A2 is expressed in the mitotic division of somatic cells.[6]
Quick Facts CCNA2, Available structures ...
CCNA2 |
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Available structures |
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PDB | Ortholog search: PDBe RCSB |
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List of PDB id codes |
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1E9H, 1FIN, 1FVV, 1GY3, 1H1P, 1H1Q, 1H1R, 1H1S, 1H24, 1H25, 1H26, 1H27, 1H28, 1JST, 1JSU, 1OGU, 1OI9, 1OIU, 1OIY, 1OKV, 1OKW, 1OL1, 1OL2, 1P5E, 1PKD, 1QMZ, 1URC, 1VYW, 2BKZ, 2BPM, 2C4G, 2C5N, 2C5O, 2C5V, 2C5X, 2C6T, 2CCH, 2CCI, 2CJM, 2I40, 2IW6, 2IW8, 2IW9, 2UUE, 2UZB, 2UZD, 2UZE, 2UZL, 2V22, 2WEV, 2WFY, 2WHB, 2WIH, 2WIP, 2WMA, 2WMB, 2WPA, 2WXV, 2X1N, 3EID, 3EJ1, 3EOC, 3F5X, 4BCK, 4BCM, 4BCN, 4BCP, 4CFM, 4CFN, 4CFU, 4CFV, 4CFW, 4CFX, 4EOI, 4EOJ, 4EOK, 4EOL, 4EOM, 4EON, 4EOO, 4EOP, 4EOQ, 4EOR, 4EOS, 4FX3, 5CYI, 5IF1 |
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Identifiers |
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Aliases | CCNA2, CCN1, CCNA, cyclin A2 |
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External IDs | OMIM: 123835; MGI: 108069; HomoloGene: 55562; GeneCards: CCNA2; OMA:CCNA2 - orthologs |
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Cyclin A2 belongs to the cyclin family, whose members regulate cell cycle progression by interacting with CDK kinases. Cyclin A2 is unique in that it can activate two different CDK kinases; it binds CDK2 during S phase, and CDK1 during the transition from G2 to M phase.[7]
Cyclin A2 is synthesized at the onset of S phase and localizes to the nucleus, where the cyclin A2-CDK2 complex is implicated in the initiation and progression of DNA synthesis. Phosphorylation of CDC6 and MCM4 by the cyclin A2-CDK2 complex prevents re-replication of DNA during the cell cycle.[6]
Cyclin A2 is involved in the G2/M transition but it cannot independently form a maturation promoting factor (MPF).[8] Recent studies have shown that the cyclin A2-CDK1 complex triggers cyclin B1-CDK1 activation which results in chromatin condensation and the breakdown of the nuclear envelope.[9]
The levels of cyclin A2 are tightly synchronized with the progression of the cell cycle.[10] Transcription initiates in late G1, peaks and plateaus in mid-S, and declines in G2.[10][6]
Cyclin A2 transcription is mostly regulated by the transcription factor E2F and begins in G1, after the R point.[10][6] Absence of cyclin A2 before the R point is due to the E2F inhibition by hypophosphorylated retinoblastoma protein (pRb). After the R point, pRb is phosphorylated and can no longer bind E2F, leading to cyclin A2 transcription.[11][12] The cyclin A2-CDK2 complex eventually phosphorylates E2F, turning off cyclin A2 transcription.[10] E2F promotes cyclin A2 transcription by de-repressing the promoter.[10][11]
Cyclin A2 has been shown to interact with:
Cyclin A2 regulates homologous recombinational DNA repair in human breast cancer cells[21] Loss of cyclin A2 causes high rates of double-strand breaks in DNA. The increase in double-strand breaks is a consequence of defective homologous recombinational repair of the breaks resulting from reduced MRE11 and RAD51 DNA repair proteins.[21] Cyclin A2 mediates the abundance of MRE11 nuclease by binding to Mre11 mRNA. Cyclin A2 mediates the abundance of RAD51 protein by inhibiting proteasome degradation of this protein.
During mouse development and aging, cyclin A2 promotes DNA repair, particularly double-strand break repair, in the brain.[22] Also in mice, cyclin A2 was found to be an RNA binding protein that controls the translation of Mre11 mRNA.[23]
Cyclin A2 (Ccna2) is a key protein involved in the direction of mammalian cardiac myocytes to grow and divide, and has been shown to induce cardiac repair following myocardial infarction.[24] Normally, Ccna2 is silenced postnatally in mammalian cardiac myocytes. Because of this gene silencing, adult heart muscle cells cannot divide readily to repair and regenerate after a heart attack.[24]
Ccna2 has been found to induce cardiac repair in small-animal models following myocardial infarction.[24] Preclinical trials involving injections of adenovirus which contained the Ccna2 gene into infarcted porcine (pig) hearts has shown to be protective of MI in pig hearts.[24] Ccna2 mediated cardiac repair showed both a decrease in fibrosis in the peri-infarct tissue and a greater number of cardiomyocytes at the sites of injection.[24] Delivery of Ccna2 into cardiac tissue invokes a regenerative response and markedly enhances cardiac function.[24][25][26]
Increased expression of cyclin A2 has been observed in many types of cancer such as breast, cervical, liver, and lung among others.[6][27][28][29][30] While it is not clear whether increased expression of cyclin A2 is a cause or result of tumorigenesis, it is indicative of prognostic values such as predictions of survival or relapse.[6]
Overexpression of cyclin A2 in mammalian cells can result in the delayed onset of metaphase and anaphase.[31] It is also possible that cyclin A2-CDK contributes to tumorigenesis by the phosphorylation of oncoproteins or tumor suppressors like p53.[32]
Henneke G, Koundrioukoff S, Hübscher U (July 2003). "Phosphorylation of human Fen1 by cyclin-dependent kinase modulates its role in replication fork regulation". Oncogene. 22 (28): 4301–4313. doi:10.1038/sj.onc.1206606. PMID 12853968. S2CID 5787920.
Ohtoshi A, Maeda T, Higashi H, Ashizawa S, Yamada M, Hatakeyama M (January 2000). "beta3-endonexin as a novel inhibitor of cyclin A-associated kinase". Biochem. Biophys. Res. Commun. 267 (3): 947–952. doi:10.1006/bbrc.1999.2007. PMID 10673397.
Joaquin M, Bessa M, Saville MK, Watson RJ (November 2002). "B-Myb overcomes a p107-mediated cell proliferation block by interacting with an N-terminal domain of p107". Oncogene. 21 (52): 7923–7932. doi:10.1038/sj.onc.1206001. PMID 12439743. S2CID 21761703.
Marti A, Wirbelauer C, Scheffner M, Krek W (May 1999). "Interaction between ubiquitin-protein ligase SCFSKP2 and E2F-1 underlies the regulation of E2F-1 degradation". Nat. Cell Biol. 1 (1): 14–19. doi:10.1038/8984. PMID 10559858. S2CID 8884226.
Shapiro SD, Ranjan AK, Kawase Y, Cheng RK, Kara RJ, Bhattacharya R, Guzman-Martinez G, Sanz J, Garcia MJ, Chaudhry HW (2014). "Cyclin A2 induces cardiac regeneration after myocardial infarction through cytokinesis of adult cardiomyocytes". Sci Transl Med. 6 (224): 224ra27. doi:10.1126/scitranslmed.3007668. PMID 24553388. S2CID 20386712.
Bukholm IR, Bukholm G, Nesland JM (Jul 2001). "Over-expression of cyclin A is highly associated with early relapse and reduced survival in patients with primary breast carcinomas". Int. J. Cancer. 93 (2): 283–287. doi:10.1002/ijc.1311. PMID 11410878. S2CID 10543682.
Ohashi R, Gao C, Miyazaki M, Hamazaki K, Tsuji T, Inoue Y, Uemura T, Hirai R, Shimizu N, Namba M (Jan–Feb 2001). "Enhanced expression of cyclin E and cyclin A in human hepatocellular carcinomas". Anticancer Res. 21 (1B): 657–662. PMID 11299822.
- Bailly E, Pines J, Hunter T, Bornens M (1992). "Cytoplasmic accumulation of cyclin B1 in human cells: association with a detergent-resistant compartment and with the centrosome". J. Cell Sci. 101 (3): 529–545. doi:10.1242/jcs.101.3.529. PMID 1387877.
- Faha B, Ewen ME, Tsai LH, Livingston DM, Harlow E (1992). "Interaction between human cyclin A and adenovirus E1A-associated p107 protein". Science. 255 (5040): 87–90. Bibcode:1992Sci...255...87F. doi:10.1126/science.1532458. PMID 1532458.
- Bandara LR, Adamczewski JP, Hunt T, La Thangue NB (1991). "Cyclin A and the retinoblastoma gene product complex with a common transcription factor". Nature. 352 (6332): 249–251. Bibcode:1991Natur.352..249B. doi:10.1038/352249a0. PMID 1830372. S2CID 1019851.
- Blanquet V, Wang JA, Chenivesse X, Henglein B, Garreau F, Bréchot C, Turleau C (1990). "Assignment of a human cyclin A gene to 4q26-q27". Genomics. 8 (3): 595–597. doi:10.1016/0888-7543(90)90052-V. PMID 1962755.
- Wang J, Chenivesse X, Henglein B, Bréchot C (1990). "Hepatitis B virus integration in a cyclin A gene in a hepatocellular carcinoma". Nature. 343 (6258): 555–557. Bibcode:1990Natur.343..555W. doi:10.1038/343555a0. PMID 1967822. S2CID 4269638.
- Jeffrey PD, Russo AA, Polyak K, Gibbs E, Hurwitz J, Massagué J, Pavletich NP (1995). "Mechanism of CDK activation revealed by the structure of a cyclinA-CDK2 complex". Nature. 376 (6538): 313–320. Bibcode:1995Natur.376..313J. doi:10.1038/376313a0. PMID 7630397. S2CID 4361179.
- Castro A, Jaumot M, Vergés M, Agell N, Bachs O (1994). "Microsomal localization of cyclin A and cdk2 in proliferating rat liver cells". Biochem. Biophys. Res. Commun. 201 (3): 1072–1078. doi:10.1006/bbrc.1994.1814. PMID 8024548.
- Dyson N, Dembski M, Fattaey A, Ngwu C, Ewen M, Helin K (1993). "Analysis of p107-associated proteins: p107 associates with a form of E2F that differs from pRB-associated E2F-1". J. Virol. 67 (12): 7641–7647. doi:10.1128/JVI.67.12.7641-7647.1993. PMC 238233. PMID 8230483.
- Li Y, Graham C, Lacy S, Duncan AM, Whyte P (1993). "The adenovirus E1A-associated 130-kD protein is encoded by a member of the retinoblastoma gene family and physically interacts with cyclins A and E". Genes Dev. 7 (12A): 2366–2377. doi:10.1101/gad.7.12a.2366. PMID 8253383.
- Lees EM, Harlow E (1993). "Sequences within the conserved cyclin box of human cyclin A are sufficient for binding to and activation of cdc2 kinase". Mol. Cell. Biol. 13 (2): 1194–1201. doi:10.1128/MCB.13.2.1194. PMC 359004. PMID 8423786.
- Sebastian B, Kakizuka A, Hunter T (1993). "Cdc25M2 activation of cyclin-dependent kinases by dephosphorylation of threonine-14 and tyrosine-15". Proc. Natl. Acad. Sci. U.S.A. 90 (8): 3521–3524. Bibcode:1993PNAS...90.3521S. doi:10.1073/pnas.90.8.3521. PMC 46332. PMID 8475101.
- Carbonaro-Hall D, Williams R, Wu L, Warburton D, Zeichner-David M, MacDougall M, Tolo V, Hall F (1993). "G1 expression and multistage dynamics of cyclin A in human osteosarcoma cells". Oncogene. 8 (6): 1649–1659. PMID 8502485.
- Meikrantz W, Schlegel R (1996). "Suppression of apoptosis by dominant negative mutants of cyclin-dependent protein kinases". J. Biol. Chem. 271 (17): 10205–10209. doi:10.1074/jbc.271.17.10205. PMID 8626584.
- Poon RY, Jiang W, Toyoshima H, Hunter T (1996). "Cyclin-dependent kinases are inactivated by a combination of p21 and Thr-14/Tyr-15 phosphorylation after UV-induced DNA damage". J. Biol. Chem. 271 (22): 13283–13291. doi:10.1074/jbc.271.22.13283. PMID 8662825.
- Russo AA, Jeffrey PD, Patten AK, Massagué J, Pavletich NP (1996). "Crystal structure of the p27Kip1 cyclin-dependent-kinase inhibitor bound to the cyclin A-Cdk2 complex". Nature. 382 (6589): 325–331. Bibcode:1996Natur.382..325R. doi:10.1038/382325a0. PMID 8684460. S2CID 4284942.
- Russo AA, Jeffrey PD, Pavletich NP (1996). "Structural basis of cyclin-dependent kinase activation by phosphorylation". Nat. Struct. Biol. 3 (8): 696–700. doi:10.1038/nsb0896-696. PMID 8756328. S2CID 383015.