Structure and functionality of a designed p53 dimer11Edited by P. E. Wright

Davison, Timothy S.; Nie, Xuegang; Ma, Weili; Lin, Yunping; Kay, Cyril M.; Benchimol, Samuel; Arrowsmith, C.H.

doi:10.1006/jmbi.2001.4450

Cited by 68 publications

(85 citation statements)

References 58 publications

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“…It has been shown by several laboratories that dimers (and such a hetero-tetramer is a functional dimer) retains approximately 50% of the activity of the tetramer. 16,17 Using TAp73β containing the homo mutants, however, did not show a reduction in activity, proving that hetero-tetramer formation was suppressed (Supplementary Figure S7B).…”

Section: Inhibition Of the Transcriptional Activity Of Tap73β Bymentioning

confidence: 95%

Mechanism of TAp73 inhibition by ΔNp63 and structural basis of p63/p73 hetero-tetramerization

et al. 2016

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Members of the p53 tumor-suppressor family are expressed as multiple isoforms. Isoforms with an N-terminal transactivation domain are transcriptionally active, while those ones lacking this domain often inhibit the transcriptional activity of other family members. In squamous cell carcinomas, the high expression level of ΔNp63α inhibits the tumor-suppressor function of TAp73β. This can in principle be due to blocking of the promoter or by direct interaction between both proteins. p63 and p73 can heterooligomerize through their tetramerization domains and a hetero-tetramer consisting of two p63 and two p73 molecules is thermodynamically more stable than both homo-tetramers. Here we show that cells expressing both p63 and p73 exist in mouse epidermis and hair follicle and that hetero-tetramer complexes can be detected by immunoprecipitation in differentiating keratinocytes. Through structure determination of the hetero-tetramer, we reveal why this hetero-tetramer is the thermodynamically preferred species. We have created mutants that exclusively form either hetero-tetramers or homo-tetramers, allowing to investigate the function of these p63/p73 hetero-tetramers. Using these tools, we show that inhibition of TAp73β in squamous cell carcinomas is due to promoter squelching and not direct interaction.

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Section: Inhibition Of the Transcriptional Activity Of Tap73β Bymentioning

confidence: 95%

Mechanism of TAp73 inhibition by ΔNp63 and structural basis of p63/p73 hetero-tetramerization

et al. 2016

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“…[16][17][18] It is a structural domain that forms a tetramer, and mutations within the OD that inhibit tetramerization of p53 result in greatly reduced transcriptional activity. 19 In addition, several protein-protein interactions and posttranslational modifications require the tetrameric state as well, 16 and mutations in the OD of p53 that prevent oligomerization have been identified in human cancers. 20,21 Owing to its functional importance, the OD of p53 has been the target of several structure determination projects.…”

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confidence: 99%

Conformational stability and activity of p73 require a second helix in the tetramerization domain

et al. 2009

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p73 and p63, the two ancestral members of the p53 family, are involved in neurogenesis, epithelial stem cell maintenance and quality control of female germ cells. The highly conserved oligomerization domain (OD) of tumor suppressor p53 is essential for its biological functions, and its structure was believed to be the prototype for all three proteins. However, we report that the ODs of p73 and p63 differ from the OD of p53 by containing an additional a-helix that is not present in the structure of the p53 OD. Deletion of this helix causes a dissociation of the OD into dimers; it also causes conformational instability and reduces the transcriptional activity of p73. Moreover, we show that ODs of p73 and p63 strongly interact and that a large number of different heterotetramers are supported by the additional helix. Detailed analysis shows that the heterotetramer consisting of two homodimers is thermodynamically more stable than the two homotetramers. No heterooligomerization between p53 and the p73/p63 subfamily was observed, supporting the notion of functional orthogonality within the p53 family. p53, a well-known tumor suppressor that is mutated in more than 50% of all human tumors, induces genes leading either to cell-cycle arrest or to apoptosis. The discovery of two proteins with a high sequence identity to p53, called p63 and p73, has sparked speculations that tumor suppression is carried out by the combined action of several members of this protein family, for example, by direct interaction through heterooligomerization. Knockout mouse studies with p63 and p73, the two ancestral members, 1 have shown functional roles distinct from p53: p63 is essential for maintaining epithelial stem cells 2,3 and for protecting the genomic stability of oocytes, 4 whereas p73 is involved in neurogenesis, sensory pathways and homeostatic control. 5 p73 is further known as an important inducer of apoptosis in response to DNA damage. 6 Although only few mutations of p63 and p73 have been found in human tumors so far, overexpression of p63 is often observed in squamous cell carcinoma, 7-10 which has been shown to suppress p73-dependent apoptosis. 11 Among all p53 family members, including those from invertebrate species, the DNA binding domain is the most conserved domain, 12-15 followed by the oligomerization domain (OD), which is indispensable for the biological function of all p53 protein family members. [16][17][18] It is a structural domain that forms a tetramer, and mutations within the OD that inhibit tetramerization of p53 result in greatly reduced transcriptional activity. 19 In addition, several protein-protein interactions and posttranslational modifications require the tetrameric state as well, 16 and mutations in the OD of p53 that prevent oligomerization have been identified in human cancers. 20,21 Owing to its functional importance, the OD of p53 has been the target of several structure determination projects. 22,23 The p53 tetramer consists of a dimer of dimers, with each monomer contributing one b-strand and o...

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“…To probe the role that oligomerization plays in p53 binding to Cul7-CPH, we performed NMR titrations using two previously designed and characterized p53 mutants, M340Q/L344R (MQLR) and L344P, which are dimeric and monomeric forms of the p53 protein, respectively (36). As shown in Fig.…”

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confidence: 99%

The Conserved CPH Domains of Cul7 and PARC Are Protein-Protein Interaction Modules That Bind the Tetramerization Domain of p53

Kaustov

Lukin

Lemak

et al. 2007

Journal of Biological Chemistry

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Cul7 is a member of the Cullin Ring Ligase (CRL) family and is required for normal mouse development and cellular proliferation. Recently, a region of Cul7 that is highly conserved in the p53-associated, Parkin-like cytoplasmic protein PARC, was shown to bind p53 directly. Here we identify the CPH domains (conserved domain within Cul7, PARC, and HERC2 proteins) of both Cul7 and PARC as p53 interaction domains using size exclusion chromatography and NMR spectroscopy. We present the first structure of the evolutionarily conserved CPH domain and provide novel insight into the Cul7-p53 interaction. The NMR structure of the Cul7-CPH domain reveals a fold similar to peptide interaction modules such as the SH3, Tudor, and KOW domains. The p53 interaction surface of both Cul7 and PARC CPH domains was mapped to a conserved surface distinct from the analogous peptide-binding regions of SH3, KOW, and Tudor domains, suggesting a novel mode of interaction. The CPH domain interaction surface of p53 resides in the tetramerization domain and is formed by residues contributed by at least two subunits.The ubiquitin-proteosome system plays an important role in controlling diverse biological processes, ranging from signal transduction to cell cycle control (1, 2). These complex processes are controlled via specific degradation of individual or groups of proteins. Protein degradation via the ubiquitin pathway involves two successive steps: tagging of the substrate by covalent attachment of multiple ubiquitin molecules (ubiquitylation) and degradation of the tagged protein by 26 S proteosome complex with release of free and reusable ubiquitin (3).Ubiquitylation is the ultimate result of coordinated activity of an enzymatic cascade, which includes a ubiquitin-activating enzyme (E1), 3 a ubiquitin-conjugating enzyme (E2), and ubiquitin-ligating (E3) enzymes. The E3 ligases are the "brain" of this process and determine substrate specificity (4, 5).Cul7, is a recently identified member of the Cullin family of ubiquitin E3 ligases, localizes predominantly in the cytoplasm (6), and forms a unique Skp1-Cul7-Fbx29-like complex with FBXW8, a WD40 containing F-box protein (7-9). Although a target substrate for FBXW8 has not been yet identified, Cul7 recruits RBX1 to form a Skp1-Cul7-Fbx29-like E3 ubiquitin ligase complex (7,8). The biological function of Cul7 is unclear.However, Cul7 appears to play an important role in development (8, 9), and overexpression of Cul7 accelerates the rate of cell proliferation (6).Cul7 has significant sequence similarity (see Fig. 1) with the p53-associated, Parkin-like cytoplasmic protein, PARC (10). Both proteins contain CPH (domain that is conserved in Cul7, PARC, and HERC2 proteins) (11), DOC (DOC1/APC10), and Cullin homology domains (see Fig. 1A) that are linked with E3 ligase function, suggesting that PARC and Cul7 may both function as E3 ubiquitin ligases. PARC has been shown to sequester p53 in the cytoplasm via interaction between the N terminus of PARC and the C terminus of p53 (10). Cul7 may perform f...

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Structure and functionality of a designed p53 dimer11Edited by P. E. Wright

Cited by 68 publications

References 58 publications

Mechanism of TAp73 inhibition by ΔNp63 and structural basis of p63/p73 hetero-tetramerization

Mechanism of TAp73 inhibition by ΔNp63 and structural basis of p63/p73 hetero-tetramerization

Conformational stability and activity of p73 require a second helix in the tetramerization domain

The Conserved CPH Domains of Cul7 and PARC Are Protein-Protein Interaction Modules That Bind the Tetramerization Domain of p53

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