1
|
Neira JL, Díaz-García C, Prieto M, Coutinho A. The C-terminal SAM domain of p73 binds to the N terminus of MDM2. Biochim Biophys Acta Gen Subj 2019; 1863:760-770. [DOI: 10.1016/j.bbagen.2019.01.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 01/25/2019] [Accepted: 01/31/2019] [Indexed: 01/10/2023]
|
2
|
p53 Family: Role of Protein Isoforms in Human Cancer. J Nucleic Acids 2011; 2012:687359. [PMID: 22007292 PMCID: PMC3191818 DOI: 10.1155/2012/687359] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 07/04/2011] [Indexed: 01/07/2023] Open
Abstract
TP53, TP63, and TP73 genes comprise the p53 family. Each gene produces protein isoforms through multiple mechanisms including extensive alternative mRNA splicing. Accumulating evidence shows that these isoforms play a critical role in the regulation of many biological processes in normal cells. Their abnormal expression contributes to tumorigenesis and has a profound effect on tumor response to curative therapy. This paper is an overview of isoform diversity in the p53 family and its role in cancer.
Collapse
|
3
|
Marabese M, Vikhanskaya F, Broggini M. p73: a chiaroscuro gene in cancer. Eur J Cancer 2007; 43:1361-72. [PMID: 17428654 DOI: 10.1016/j.ejca.2007.01.042] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Revised: 01/19/2007] [Accepted: 01/25/2007] [Indexed: 11/24/2022]
Abstract
p73 is a member of the p53 family which is gaining increasing importance in the field of cancer. Its structural homology with p53 led to the assumption that it could act as a new tumour suppressor gene. Increasing knowledge of its function, however, has cast doubts on this role. A particularly interesting characteristic of p73 is that the cell contains different isoforms with distinct and sometimes opposite functions. Evidence in the last few years clearly indicates that p73 does share some activities with p53 but also that it has some distinct functions. This review focuses on p73's role in the development and progression of cancer, analysing the gene structure and regulation and discussing similarities with p53 and differences. Recent results obtained with specific detection methods on the levels and functions of the different isoforms in tumours are also discussed.
Collapse
Affiliation(s)
- Mirko Marabese
- Laboratory of Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri, Via Eritrea 62, 20157 Milan, Italy.
| | | | | |
Collapse
|
4
|
Boominathan L. Some facts and thoughts: p73 as a tumor suppressor gene in the network of tumor suppressors. Mol Cancer 2007; 6:27. [PMID: 17407586 PMCID: PMC1853109 DOI: 10.1186/1476-4598-6-27] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2007] [Accepted: 04/03/2007] [Indexed: 12/30/2022] Open
Abstract
The question of whether p73 is a tumor suppressor gene, is not yet answered with full confidence. The lack of spontaneous tumor formation in p73 null mice and infrequent p73 mutations seen in a variety of cancers analyzed would straightaway negate its role as a primary tumor suppressor gene. However, accumulating evidence suggest that p73 gene and its target genes are hypermethylated in the cancer of lymphoid origin. Here I discuss some facts and thoughts that support the idea that p73 could still be a tumor suppressor gene. The tumor suppressor network in which p73 appears to be a participant involves E2F1, JunB, INK4a/p16, ARF/p19, p57kip2 and BRCA1. Knock out of each gene in E2F-1-p73-JunB-p16INK4a network of tumor suppressor proteins result in lymphoma/leukemia formation. Further, I tried to explain why lymphomas are not seen in p73 null mice and why p73 gene is not prone to frequent mutation.
Collapse
|
5
|
Munarriz E, Bano D, Sayan AE, Rossi M, Melino G, Nicotera P. Calpain cleavage regulates the protein stability of p73. Biochem Biophys Res Commun 2005; 333:954-60. [PMID: 15975558 DOI: 10.1016/j.bbrc.2005.05.188] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2005] [Accepted: 05/24/2005] [Indexed: 10/25/2022]
Abstract
The function of p73, a transcription factor belonging to the p53 family, is finely regulated by its steady-state protein stability. p73 protein degradation/stabilization can be regulated by mechanisms in part dependent on the ubiquitin proteasome system (UPS): (i) Itch/NEDD4-like UPS degradation, (ii) NEDD8 UPS degradation, and (iii) NQO1 20S proteasome-dependent (but ubiquitin-independent) breakdown. Here, we show that, in vitro, Calpain I can cleave p73 at two distinct sites: the first proline-rich region and within the oligomerization domain. Consequently, different p73 isoforms can be degraded by calpains, i.e., both N-terminal isoforms (TAp73 and DeltaNp73) as well as the C-terminal isoforms (alpha, beta, gamma, delta). Moreover, overexpression of the specific endogenous calpain inhibitor, calpastatin, in cultured cells increased the steady-state p73 level. This suggests that calpains may play a physiological role in the regulation of p73 protein stability.
Collapse
Affiliation(s)
- Eliana Munarriz
- Medical Research Council, Toxicology Unit, University of Leicester, Leicester LE1 9HN, UK
| | | | | | | | | | | |
Collapse
|
6
|
Oberst A, Rossi M, Salomoni P, Pandolfi PP, Oren M, Melino G, Bernassola F. Regulation of the p73 protein stability and degradation. Biochem Biophys Res Commun 2005; 331:707-12. [PMID: 15865926 DOI: 10.1016/j.bbrc.2005.03.158] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2005] [Indexed: 10/25/2022]
Abstract
p73, a homologue to the tumor suppressor gene p53, is involved in tumorigenesis, though its specific role remains unclear. The gene has two distinct promoters which allow the formation of two protein isoforms with opposite effects: full-length transactivating (TA) p73 shows pro-apoptotic effects, while the shorter DeltaNp73, which lacks the N-terminal transactivating domain, has an evident anti-apoptotic function. Unlike p53, the p73 gene is rarely mutated in human cancers. However, alterations in the relative levels of TA and DeltaNp73 have been shown to correlate with prognosis in several human cancers, suggesting that the fine regulation of these two isoforms is of pivotal importance in controlling proliferation and cell death. Much effort is currently focused on the elucidation of the mechanisms that differentially control TA and DeltaNp73 activity and protein stability, a process complicated by the finding that both proteins are regulated by a similar suite of complex post-translational modifications that include ubiquitination, sequential phosphorylation, prolyl-isomerization, recruitment into the PML-nuclear body (PML-NB), and acetylation. Here we shall consider the main regulatory partners of p73, with particular attention to the recently discovered Itch- and Nedd8-mediated degradation pathways, along with the emerging roles of PML, p38 MAP kinase, Pin1, and p300 in p73 transcriptional activation, and possible mechanisms for the differential regulation of the TAp73 and DeltaNp73 isoforms.
Collapse
Affiliation(s)
- Andrew Oberst
- IDI-IRCCS Biochemistry Lab, c/o Department of Experimental Medicine, University of Rome Tor Vergata, Rome 00133, Italy
| | | | | | | | | | | | | |
Collapse
|
7
|
Ramadan S, Terrinoni A, Catani MV, Sayan AE, Knight RA, Mueller M, Krammer PH, Melino G, Candi E. p73 induces apoptosis by different mechanisms. Biochem Biophys Res Commun 2005; 331:713-7. [PMID: 15865927 DOI: 10.1016/j.bbrc.2005.03.156] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2005] [Indexed: 11/22/2022]
Abstract
p73, like its homologue, the tumor suppressor p53, is able to induce apoptosis in several cell types. This property is important for the involvement of p73 in cancer development and therapy. However, in contrast with p53, the TAp73 gene has two distinct promoters coding for two protein isoforms with opposite effects: while the transactivation proficient TAp73 shows pro-apoptotic effects, the amino-terminal-deleted DeltaNp73 has an anti-apoptotic function. Indeed, the relative expression of these two proteins is related to the prognosis of several cancers. Here we discuss recent developments in the control of p73-induced apoptosis. First, TAp73 induces ER stress via the direct transactivation of Scotin. Second, TAp73 induces the mitochondrial pathway by directly transactivating both Bax and the BH3 only protein PUMA promoters. While the first transactivation is weak, and not sufficient to trigger apoptosis (at least in the in vitro cellular models so far evaluated), the induction of PUMA is strong and lethal. Third, the promoter of the death receptor CD95 contains a p53 responsive element and preliminary experiments suggest that TAp73 also activates the death receptor pathway. In addition, TAp73 is able to transactivate its own second promoter, thus inducing the expression of the anti-apoptotic DeltaNp73 isoform. Therefore, the balance between TAp73 and DeltaNp73 finely regulates cellular sensitivity to death.
Collapse
Affiliation(s)
- Saafa Ramadan
- Laboratory of Biochemistry and Molecular Biology, IRCCS-Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Rossi M, De Laurenzi V, Munarriz E, Green DR, Liu YC, Vousden KH, Cesareni G, Melino G. The ubiquitin-protein ligase Itch regulates p73 stability. EMBO J 2005; 24:836-48. [PMID: 15678106 PMCID: PMC549609 DOI: 10.1038/sj.emboj.7600444] [Citation(s) in RCA: 248] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2004] [Accepted: 09/21/2004] [Indexed: 11/09/2022] Open
Abstract
p73, a member of the p53 family of transcription factors, is upregulated in response to DNA damage, inducing cell cycle arrest and apoptosis. Besides indications that this p73 response is post-transcriptional, little is known about the underlying molecular mechanisms of p73 protein degradation. Ubiquitination and proteasomal-dependent degradation of p53 are regulated by its transcriptional target MDM2. However, unlike p53, p73 binds to, but is not degraded by, MDM2. Here we describe the binding of p73 to Itch, a Hect ubiquitin-protein ligase. Itch selectively binds and ubiquitinates p73 but not p53; this results in the rapid proteasome-dependent degradation of p73. Upon DNA damage Itch itself is downregulated, allowing p73 protein levels to rise and thus interfere with p73 function. In conclusion, we have identified a key mechanism in the control of p73 protein levels both in normal as well as in stress conditions.
Collapse
Affiliation(s)
- Mario Rossi
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
- Medical Research Council, Toxicology Unit, Leicester University, Leicester, UK
| | - Vincenzo De Laurenzi
- Biochemistry Laboratory, IDI-IRCCS, C/O Department of Experimental Medicine and Biochemical Sciences, University of Rome ‘Tor Vergata', Rome, Italy
- Medical Research Council, Toxicology Unit, Leicester University, Leicester, UK
| | - Eliana Munarriz
- Medical Research Council, Toxicology Unit, Leicester University, Leicester, UK
| | - Douglas R Green
- La Jolla Institute for Allergy and Immunology, San Diego, CA, USA
| | - Yun-Cai Liu
- La Jolla Institute for Allergy and Immunology, San Diego, CA, USA
| | - Karen H Vousden
- Beatson Institute for Cancer Research, Garscube Estate, Bearsden, Glasgow, UK
| | - Gianni Cesareni
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
- Department of Biology, University of Rome ‘Tor Vergata', Via della Ricerca Scientifica, Rome 00133, Italy. Tel.: +39 06 72594315; Fax: +39 06 2023500; E-mail:
| | - Gerry Melino
- Biochemistry Laboratory, IDI-IRCCS, C/O Department of Experimental Medicine and Biochemical Sciences, University of Rome ‘Tor Vergata', Rome, Italy
- Medical Research Council, Toxicology Unit, Leicester University, Leicester, UK
- Medical Research Council, Toxicology Unit, Hodgkin Building, Leicester University, Lancaster Road, PO Box 138, Leicester LE1 9HN, UK. Tel.: +44 116 252 5551; Fax: +44 116 252 5616; E-mail:
| |
Collapse
|
9
|
Falconi M, Melino G, Desideri A. Molecular dynamics simulation of the C-terminal sterile α-motif domain of human p73α: evidence of a dynamical relationship between helices 3 and 5. Biochem Biophys Res Commun 2004; 316:1037-42. [PMID: 15044089 DOI: 10.1016/j.bbrc.2004.02.146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2004] [Indexed: 10/26/2022]
Abstract
We used molecular dynamics simulation to evaluate the association properties of C-terminal sterile alpha-motif (SAM) domain of human p73alpha. To test the dimerization propensity of this structure we carried out four simulations: EphB2 X-ray dimer, p73 modeled dimer, p73 NMR monomer, and p73 modeled monomer with an elongated helix 5. The results show a direct interaction between helix 5 and helix 3 since a conformational collapse of helix 3 is observed when dimer contact and/or an elongation of helix 5 is introduced by modeling in p73 SAM domain. On the basis of these results we suggest that the recognition properties of the SAM domains may be modulated by the conformational state of helix 5.
Collapse
Affiliation(s)
- Mattia Falconi
- INFM and Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy
| | | | | |
Collapse
|