The adenovirus E4orf6 E3 ubiquitin ligase complex assembles in a novel fashion

Cheng, Chi Ying; Blanchette, Paola; Branton, Philip E.

doi:10.1016/j.virol.2007.02.012

Cited by 33 publications

(14 citation statements)

References 29 publications

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“…From studies with cellular ligases, the BC-box motif was identified as (STP)LXXX(CSA)XXX⌽ (29,30). As noted earlier, the HAdV-5 E4orf6 protein contains three functional BC boxes (31,32,45). Our studies on the HAdV-5 BC boxes also showed that the first residue of this motif is not important and that a glycine can replace the hydrophobic residue at the last position.…”

Section: Analysis Of E4orf6 Proteins From Primate Mastadenoviruses (I)supporting

confidence: 61%

“…In our studies on HAdV-5 (HAdV-C), we showed that the E3 ubiquitin ligase complex assembled by E4orf6 and E1B55K (14) requires the presence in E4orf6 of a BC box (in fact, it contains three) (31,32) that enables complex formation with the cellular proteins Cul5, Elongins B and C, and RBX1 before binding to E1B55K, which functions as the major substrate recognition protein (31,32). Formation of this ligase complex was shown to be an important function of E4orf6 during infection, as a BC-box mutant unable to form the complex exhibited the same defective phenotype as that of a mutant lacking E4orf6 entirely (33).…”

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confidence: 99%

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Using the E4orf6-Based E3 Ubiquitin Ligase as a Tool To Analyze the Evolution of Adenoviruses

Gilson

Blanchette

Ballmann

et al. 2016

J Virol

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E4orf6 proteins from all human adenoviruses form Cullin-based ubiquitin ligase complexes that, in association with E1B55K, target cellular proteins for degradation. While most are assembled with Cul5, a few utilize Cul2. BC-box motifs enable all these E4orf6 proteins to assemble ligase complexes with Elongins B and C. We also identified a Cul2-box motif used for Cul2 selection in all Cul2-based complexes. With this information, we set out to determine if other adenoviruses also possess the ability to form the ligase complex and, if so, to predict their Cullin usage. Here we report that all adenoviruses known to encode an E4orf6-like protein (mastadenoviruses and atadenoviruses) maintain the potential to form the ligase complex. We could accurately predict Cullin usage for E4orf6 products of mastadenoviruses and all but one atadenovirus. Interestingly, in nonhuman primate adenoviruses, we found a clear segregation of Cullin binding, with Cul5 utilized by viruses infecting great apes and Cul2 by Old/New World monkey viruses, suggesting that a switch from Cul2 to Cul5 binding occurred during the period when great apes diverged from monkeys. Based on the analysis of Cullin selection, we also suggest that the majority of human adenoviruses, which exhibit a broader tropism for the eye and the respiratory tract, exhibit Cul5 specificity and resemble viruses infecting great apes, whereas those that infect the gastrointestinal tract may have originated from monkey viruses that share Cul2 specificity. Finally, aviadenoviruses also appear to contain E4orf6 genes that encode proteins with a conserved XCXC motif followed by, in most cases, a BC-box motif. IMPORTANCETwo early adenoviral proteins, E4orf6 and E1B55K, form a ubiquitin ligase complex with cellular proteins to ubiquitinate specific substrates, leading to their degradation by the proteasome. In studies with representatives of each human adenovirus species, we (and others) previously discovered that some viruses use Cul2 to form the complex, while others use Cul5. In the present study, we expanded our analyses to all sequenced adenoviruses and found that E4orf6 genes from all mast-and atadenoviruses encode proteins containing the motifs necessary to form the ligase complex. We found a clear separation in Cullin specificity between adenoviruses of great apes and Old/New World monkeys, lending support for a monkey origin for human viruses of the Human mastadenovirus A, F, and G species. We also identified previously unrecognized E4orf6 genes in the aviadenoviruses that encode proteins containing motifs permitting formation of the ubiquitin ligase.

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Section: Analysis Of E4orf6 Proteins From Primate Mastadenoviruses (I)supporting

confidence: 61%

mentioning

confidence: 99%

Using the E4orf6-Based E3 Ubiquitin Ligase as a Tool To Analyze the Evolution of Adenoviruses

Gilson

Blanchette

Ballmann

et al. 2016

J Virol

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“…The human adenovirus type 5 (Ad5) early region 4 34-kDa product from open reading frame 6 (E4orf6) contains three BC boxes (Blanchette et al, 2004; Cheng et al, 2007, 2011). Although Ad5 E4orf6 forms complex containing Cul5, Elongin BC complex, and Rbx1, Cul5 box is not present in the Ad5 E4orf6 (Harada et al, 2002; Blanchette et al, 2004; Cheng et al, 2011).…”

Section: Viral Ecs-type Ubiquitin Ligasementioning

confidence: 99%

“…Although Ad5 E4orf6 forms complex containing Cul5, Elongin BC complex, and Rbx1, Cul5 box is not present in the Ad5 E4orf6 (Harada et al, 2002; Blanchette et al, 2004; Cheng et al, 2011). Adenoviral protein E1B55K associates with the E4orf6 protein and recognizes substrate to be degraded by ubiquitin–proteasome pathway (Blanchette et al, 2004; Cheng et al, 2007; Luo et al, 2007). This complex is essential for efficient viral replication and some substrates have been identified, including p53 (Moore et al, 1996; Querido et al, 1997; Steegenga et al, 1998; Cathomen and Weitzman, 2000; Nevels et al, 2000; Shen et al, 2001), meiotic recombination 11 (Mre11; Stracker et al, 2002; Blanchette et al, 2004), DNA ligase IV (Baker et al, 2007), integrin α3 (Dallaire et al, 2009), and adeno-associated virus type 5 (AAV5) Rep52 and capsid proteins (Nayak et al, 2008).…”

Section: Viral Ecs-type Ubiquitin Ligasementioning

confidence: 99%

The Role of Elongin BC-Containing Ubiquitin Ligases

Okumura¹,

Matsuzaki²,

Nakatsukasa³

et al. 2012

Front. Oncol.

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The Elongin complex was originally identified as a positive regulator of RNA polymerase II and is composed of a transcriptionally active subunit (A) and two regulatory subunits (B and C). The Elongin BC complex enhances the transcriptional activity of Elongin A. “Classical” SOCS box-containing proteins interact with the Elongin BC complex and have ubiquitin ligase activity. They also interact with the scaffold protein Cullin (Cul) and the RING domain protein Rbx and thereby are members of the Cullin RING ligase (CRL) superfamily. The Elongin BC complex acts as an adaptor connecting Cul and SOCS box proteins. Recently, it was demonstrated that classical SOCS box proteins can be further divided into two groups, Cul2- and Cul5-type proteins. The classical SOCS box-containing protein pVHL is now classified as a Cul2-type protein. The Elongin BC complex containing CRL family is now considered two distinct protein assemblies, which play an important role in regulating a variety of cellular processes such as tumorigenesis, signal transduction, cell motility, and differentiation.

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“…Furthermore, no impact of the E1B 55-kDa protein on inhibition of the p53-dependent transcriptional program was detected in a genome-wide comparison of cellular gene expression in normal human cells infected by Ad5 and such a mutant (48). These observations indicate that, while the E1B 55-kDa protein and the E3 ubiquitin ligase in which it serves as the substrate recognition subunit (49)(50)(51)(52) are necessary to prevent accumulation of p53, it is not responsible for inhibition of transcriptional activation (or repression) by p53. This function has been ascribed more recently to the E4 Orf3 protein: expression of p53-responsive genes was reported to be increased in cells infected by a mutant virus null for production of both the E1B 55-kDa and E4 Orf3 proteins compared to those infected by the wild-type virus or an E1B 55-kDa-null mutant (53).…”

Section: The Tumor Suppressor P53 a Master Regulator Of Cellular Resmentioning

confidence: 90%

Impact of the Adenoviral E4 Orf3 Protein on the Activity and Posttranslational Modification of p53

DeHart

Perlman

Flint

2015

J Virol

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Our previous studies have established that the p53 populations that accumulate in normal human cells exposed to etoposide or infected by an E1B 55-kDa protein-null mutant of human adenovirus type 5 carry a large number of posttranslational modifications at numerous residues (C. J. DeHart, J. S. Chahal, S. J. Flint, and D. H. Perlman, Mol Cell Proteomics 13:1-17, 2014, http: //dx.doi.org/10.1074/mcp.M113.030254). In the absence of this E1B protein, the p53 transcriptional program is not induced, and it has been reported that the viral E4 Orf3 protein inactivates p53 (C. Soria, F. E. Estermann, K. C. Espantman, and C. C. O'Shea, Nature 466:1076 -1081, 2010, http://dx.doi.org/10.1038/nature09307). As the latter protein disrupts nuclear Pml bodies, sites at which p53 is modified, we used mass spectrometry to catalogue the posttranscriptional modifications of the p53 population that accumulates when neither the E1B 55-kDa nor the E4 Orf3 protein is made in infected cells. Eighty-five residues carrying 163 modifications were identified. The overall patterns of posttranslational modification of this population and p53 present in cells infected by an E1B 55-kDa-null mutant were similar. The efficiencies with which the two forms of p53 bound to a consensus DNA recognition sequence could not be distinguished and were lower than that of transcriptionally active p53. The absence of the E4 Orf3 protein increased expression of several p53-responsive genes when the E1B protein was also absent from infected cells. However, expression of these genes did not attain the levels observed when p53 was activated in response to etoposide treatment and remained lower than those measured in mock-infected cells. T he cellular p53 protein was discovered by virtue of its interaction with the major product of the simian virus 40 oncogene, large T antigen (1, 2). The p53 tumor suppressor is a master regulator of cellular responses to internal and external stresses, when it can induce inhibition of cell cycle progression, apoptosis, or other responses, such as changes in metabolism. Under normal conditions, the human p53 protein is maintained at low concentrations, for example, as a result of its targeting for proteasomal degradation by the E3 ubiquitin ligase Hdm2 (3-5). Once stabilized and activated in response to genotoxic and other forms of stress, p53 binds to specific promoter sequences to activate or repress the transcription of numerous target genes (6-10) and can also operate in the cytoplasm to induce apoptosis by transcription-independent mechanisms (reviewed in references 11 to 14).One of the first interactions between human adenovirus type 5 (Ad5) and cellular proteins to be identified was the association of the viral E1B 55-kDa protein with p53 (15). In view of its crucial roles in regulating cell survival and other aspects of cellular physiology, considerable effort has since been devoted to elucidation of the impacts of adenoviral gene products on the activities and properties of p53. The viral immediate-early E1A prote...

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The adenovirus E4orf6 E3 ubiquitin ligase complex assembles in a novel fashion

Cited by 33 publications

References 29 publications

Using the E4orf6-Based E3 Ubiquitin Ligase as a Tool To Analyze the Evolution of Adenoviruses

Using the E4orf6-Based E3 Ubiquitin Ligase as a Tool To Analyze the Evolution of Adenoviruses

The Role of Elongin BC-Containing Ubiquitin Ligases

Impact of the Adenoviral E4 Orf3 Protein on the Activity and Posttranslational Modification of p53

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