Mammalian protein found in Homo sapiens From Wikipedia, the free encyclopedia
Proliferating cell nuclear antigen (PCNA) is a DNA clamp that acts as a processivity factor for DNA polymerase δ in eukaryoticcells and is essential for replication. PCNA is a homotrimer and achieves its processivity by encircling the DNA, where it acts as a scaffold to recruit proteins involved in DNA replication, DNA repair, chromatin remodeling and epigenetics.[5]
Many proteins interact with PCNA via the two known PCNA-interacting motifs PCNA-interacting peptide (PIP) box[6] and AlkB homologue 2 PCNA interacting motif (APIM).[7] Proteins binding to PCNA via the PIP-box are mainly involved in DNA replication whereas proteins binding to PCNA via APIM are mainly important in the context of genotoxic stress.[8]
The protein encoded by this gene is found in the nucleus and is a cofactor of DNA polymerase delta. The encoded protein acts as a homotrimer and helps increase the processivity of leading strand synthesis during DNA replication. In response to DNA damage, this protein is ubiquitinated and is involved in the RAD6-dependent DNA repair pathway. Two transcript variants encoding the same protein have been found for this gene. Pseudogenes of this gene have been described on chromosome 4 and on the X chromosome.[9]
PCNA is also found in archaea, as a processivity factor of polD, the single multi-functional DNA polymerase in this domain of life.[10]
PCNA was originally identified as an antigen that is expressed in the nuclei of cells during the DNA synthesis phase of the cell cycle.[11] Part of the protein was sequenced and that sequence was used to allow isolation of a cDNA clone.[12] PCNA helps hold DNA polymerase delta (Pol δ) to DNA. PCNA is clamped[13] to DNA through the action of replication factor C (RFC),[14] which is a heteropentameric member of the AAA+ class of ATPases. Expression of PCNA is under the control of E2Ftranscription factor-containing complexes.[15][16]
Since DNA polymerase epsilon is involved in resynthesis of excised damaged DNA strands during DNA repair, PCNA is important for both DNA synthesis and DNA repair.[17][18]
PCNA is also involved in the DNA damage tolerance pathway known as post-replication repair (PRR).[19] In PRR, there are two sub-pathways:
(1) a translesion synthesis pathway, which is carried out by specialised DNA polymerases that are able to incorporate damaged DNA bases into their active sites (unlike the normal replicative polymerase, which stall), and hence bypass the damage, and
(2) a proposed "template switch" pathway that is thought to involve damage bypass by recruitment of the homologous recombination machinery.
PCNA is pivotal to the activation of these pathways and the choice as to which pathway is utilised by the cell. PCNA becomes post-translationally modified by ubiquitin.[20] Mono-ubiquitin of lysine number 164 on PCNA activates the translesion synthesis pathway. Extension of this mono-ubiquitin by a non-canonical lysine-63-linked poly-ubiquitin chain on PCNA[20] is thought to activate the template switch pathway. Furthermore, sumoylation (by small ubiquitin-like modifier, SUMO) of PCNA lysine-164 (and to a lesser extent, lysine-127) inhibits the template switch pathway.[20] This antagonistic effect occurs because sumoylated PCNA recruits a DNA helicase called Srs2,[21] which has a role in disrupting Rad51 nucleoprotein filaments fundamental for initiation of homologous recombination.
Proteins interacting with PCNA via APIM include human AlkB homologue 2, TFIIS-L, TFII-I, Rad51B,[7] XPA,[88] ZRANB3,[89] and FBH1.[90]
Antibodies against proliferating cell nuclear antigen (PCNA) or monoclonal antibody termed Ki-67 can be used for grading of different neoplasms, e.g. astrocytoma. They can be of diagnostic and prognostic value. Imaging of the nuclear distribution of PCNA (via antibody labeling) can be used to distinguish between early, mid and late S phase of the cell cycle.[91] However, an important limitation of antibodies is that cells need to be fixed leading to potential artifacts.
On the other hand, the study of the dynamics of replication and repair in living cells can be done by introducing translational fusions of PCNA. To eliminate the need for transfection and bypass the problem of difficult to transfect and/or short lived cells, cell permeable replication and/or repair markers can be used. These peptides offer the distinct advantage that they can be used in situ in living tissue and even distinguish cells undergoing replication from cells undergoing repair.[92]
caPCNA, a post-translationally modified isoform of PCNA common in cancer cells, is a potential therapeutic target in cancer therapy.[93][94] In 2023 City of Hope National Medical Center published preclinical research on a targeted chemotherapy using AOH1996 that appears to suppress tumor growth without causing discernable side effects.[95]
Rountree MR, Bachman KE, Baylin SB (July 2000). "DNMT1 binds HDAC2 and a new co-repressor, DMAP1, to form a complex at replication foci". Nature Genetics. 25 (3): 269–277. doi:10.1038/77023. PMID10888872. S2CID26149386.
Chuang LS, Ian HI, Koh TW, Ng HH, Xu G, Li BF (September 1997). "Human DNA-(cytosine-5) methyltransferase-PCNA complex as a target for p21WAF1". Science. 277 (5334): 1996–2000. doi:10.1126/science.277.5334.1996. PMID9302295.
Dianova II, Bohr VA, Dianov GL (October 2001). "Interaction of human AP endonuclease 1 with flap endonuclease 1 and proliferating cell nuclear antigen involved in long-patch base excision repair". Biochemistry. 40 (42): 12639–12644. doi:10.1021/bi011117i. PMID11601988.
Chen IT, Smith ML, O'Connor PM, Fornace AJ (November 1995). "Direct interaction of Gadd45 with PCNA and evidence for competitive interaction of Gadd45 and p21Waf1/Cip1 with PCNA". Oncogene. 11 (10): 1931–7. PMID7478510.
Hall PA, Kearsey JM, Coates PJ, Norman DG, Warbrick E, Cox LS (June 1995). "Characterisation of the interaction between PCNA and Gadd45". Oncogene. 10 (12): 2427–33. PMID7784094.
Scott M, Bonnefin P, Vieyra D, Boisvert FM, Young D, Bazett-Jones DP, Riabowol K (October 2001). "UV-induced binding of ING1 to PCNA regulates the induction of apoptosis". J. Cell Sci. 114 (Pt 19): 3455–62. doi:10.1242/jcs.114.19.3455. PMID11682605.
Matheos D, Ruiz MT, Price GB, Zannis-Hadjopoulos M (October 2002). "Ku antigen, an origin-specific binding protein that associates with replication proteins, is required for mammalian DNA replication". Biochim. Biophys. Acta. 1578 (1–3): 59–72. doi:10.1016/s0167-4781(02)00497-9. PMID12393188.
Rual JF, Venkatesan K, Hao T, Hirozane-Kishikawa T, Dricot A, Li N, Berriz GF, Gibbons FD, Dreze M, Ayivi-Guedehoussou N, Klitgord N, Simon C, Boxem M, Milstein S, Rosenberg J, Goldberg DS, Zhang LV, Wong SL, Franklin G, Li S, Albala JS, Lim J, Fraughton C, Llamosas E, Cevik S, Bex C, Lamesch P, Sikorski RS, Vandenhaute J, Zoghbi HY, Smolyar A, Bosak S, Sequerra R, Doucette-Stamm L, Cusick ME, Hill DE, Roth FP, Vidal M (October 2005). "Towards a proteome-scale map of the human protein-protein interaction network". Nature. 437 (7062): 1173–8. Bibcode:2005Natur.437.1173R. doi:10.1038/nature04209. PMID16189514. S2CID4427026.
Shimazaki N, Yoshida K, Kobayashi T, Toji S, Tamai K, Koiwai O (July 2002). "Over-expression of human DNA polymerase lambda in E. coli and characterization of the recombinant enzyme". Genes Cells. 7 (7): 639–51. doi:10.1046/j.1365-2443.2002.00547.x. PMID12081642. S2CID29714829.
van der Kuip H, Carius B, Haque SJ, Williams BR, Huber C, Fischer T (April 1999). "The DNA-binding subunit p140 of replication factor C is upregulated in cycling cells and associates with G1 phase cell cycle regulatory proteins". J. Mol. Med. 77 (4): 386–92. doi:10.1007/s001090050365. PMID10353443. S2CID22183443.
Rodríguez-López AM, Jackson DA, Nehlin JO, Iborra F, Warren AV, Cox LS (February 2003). "Characterisation of the interaction between WRN, the helicase/exonuclease defective in progeroid Werner's syndrome, and an essential replication factor, PCNA". Mechanisms of Ageing and Development. 124 (2): 167–174. doi:10.1016/s0047-6374(02)00131-8. PMID12633936. S2CID37287691.
Ise T, Nagatani G, Imamura T, Kato K, Takano H, Nomoto M, etal. (January 1999). "Transcription factor Y-box binding protein 1 binds preferentially to cisplatin-modified DNA and interacts with proliferating cell nuclear antigen". Cancer Research. 59 (2): 342–346. PMID9927044.
Wang SC (April 2014). "PCNA: a silent housekeeper or a potential therapeutic target?". Trends in Pharmacological Sciences. 35 (4): 178–186. doi:10.1016/j.tips.2014.02.004. PMID24655521.
Chen IT, Smith ML, O'Connor PM, Fornace AJ (November 1995). "Direct interaction of Gadd45 with PCNA and evidence for competitive interaction of Gadd45 and p21Waf1/Cip1 with PCNA". Oncogene. 11 (10): 1931–1937. PMID7478510.
Hall PA, Kearsey JM, Coates PJ, Norman DG, Warbrick E, Cox LS (June 1995). "Characterisation of the interaction between PCNA and Gadd45". Oncogene. 10 (12): 2427–2433. PMID7784094.
Kato S, Sekine S, Oh SW, Kim NS, Umezawa Y, Abe N, etal. (December 1994). "Construction of a human full-length cDNA bank". Gene. 150 (2): 243–250. doi:10.1016/0378-1119(94)90433-2. PMID7821789.
Kemeny MM, Alava G, Oliver JM (November 1992). "Improving responses in hepatomas with circadian-patterned hepatic artery infusions of recombinant interleukin-2". Journal of Immunotherapy. 12 (4): 219–223. doi:10.1097/00002371-199211000-00001. PMID1477073.
Prelich G, Kostura M, Marshak DR, Mathews MB, Stillman B (1987). "The cell-cycle regulated proliferating cell nuclear antigen is required for SV40 DNA replication in vitro". Nature. 326 (6112): 471–475. Bibcode:1987Natur.326..471P. doi:10.1038/326471a0. PMID2882422. S2CID4336365.
Webb G, Parsons P, Chenevix-Trench G (November 1990). "Localization of the gene for human proliferating nuclear antigen/cyclin by in situ hybridization". Human Genetics. 86 (1): 84–86. doi:10.1007/bf00205180. PMID1979311. S2CID27107553.