Characterization of the nuclear localization signal of high risk HPV16 E2 protein

Klucevsek, Kristin M.; Wertz, Mary H.; Lucchi, John; Leszczynski, Anna; Moroianu, Junona

doi:10.1016/j.virol.2006.10.018

Cited by 14 publications

(15 citation statements)

References 23 publications

(21 reference statements)

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“…Sumoylation is also known to affect cellular localization of target proteins (Wilson and Rangasamy, 2001), and lysine 292 is just upstream of the nuclear localization sequence of HPV16 E2 (Klucevsek et al, 2007). Hence, it was important to determine if the subcellular localization of 16E2 was influenced by the K292R mutation which could result in differences in transcriptional activities.…”

Section: Resultsmentioning

confidence: 99%

Modification of papillomavirus E2 proteins by the small ubiquitin-like modifier family members (SUMOs)

Roark

Bian

et al. 2008

Virology

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Papillomavirus E2 proteins are critical regulatory proteins that function in replication, genome segregation, and viral transcription, including control of expression of the viral oncogenes, E6 and E7. Sumoylation is a post-translational modification that has been shown to target and modulate the function of many transcription factors, and we now demonstrate that E2 proteins are sumoylated. Both bovine and human papillomavirus E2 proteins bind to the SUMO conjugation enzyme, Ubc9, and using in vitro and E. coli sumoylation systems, these E2 proteins were readily modified by SUMO proteins. In vivo experiments further confirmed that E2 can be sumoylated by SUMO1, SUMO2, or SUMO3. Mapping studies identified lysine 292 as the principal residue for covalent conjugation of SUMO to HPV16 E2, and a lysine 292 to arginine mutant showed defects for both transcriptional activation and repression. The expression levels, intracellular localization, and the DNA-binding activity of HPV16 E2 were unchanged by this K292R mutation, suggesting that the transcriptional defect reflects a functional contribution by sumoylation at this residue. This study provides evidence that sumoylation has a role in the regulation of papillomavirus E2, and identifies a new mechanism for the modulation of E2 function at the post-translational level.

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Section: Resultsmentioning

confidence: 99%

Modification of papillomavirus E2 proteins by the small ubiquitin-like modifier family members (SUMOs)

Roark

Bian

et al. 2008

Virology

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“…One is the recognition helix in the DNA binding domain and this fits the criteria of a classical NLS in that it is required for nuclear localization and is transplantable to another protein (Skiadopoulos and McBride, 1996). In vitro studies confirm that this region is also the NLS for HPV16 E2 (Klucevsek et al, 2007). The second putative BPV1 NLS, PKRCFKKGARV, is in the fulcrum of the transactivation domain and contains two highly conserved lysine residues (111, 112).…”

Section: Localizationmentioning

confidence: 86%

“…However, there is one report on nuclear-cytoplasmic shuttling of high risk E2 proteins (Blachon et al, 2005). Nuclear localization signals (NLS) have been mapped in BPV1, HPV11 and HPV16 (Klucevsek et al, 2007; Skiadopoulos and McBride, 1996; Zou et al, 2000) and alpha importins 3 and 5 bind specifically to these proteins (Bian and Wilson, 2010). In BPV1 there are two potential NLSs.…”

Section: Localizationmentioning

confidence: 99%

The Papillomavirus E2 proteins

2013

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The papillomavirus E2 proteins are pivotal to the viral life cycle and have well characterized functions in transcriptional regulation, initiation of DNA replication and partitioning the viral genome. The E2 proteins also function in vegetative DNA replication, post-transcriptional processes and possibly packaging. This review describes structural and functional aspects of the E2 proteins and their binding sites on the viral genome. It is intended to be a reference guide to this viral protein.

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“…The L1 major and L2 minor capsid proteins of both high risk and low risk HPVs have classical basic monopartite and bipartite NLSs (Bordeaux et al, 2006; Darshan et al, 2004; Klucevsek et al, 2006; Merle et al, 1999; Nelson, Rose, and Moroianu, 2002; Sun et al, 1995). Low risk HPV11 E2 has a classical monopartite NLS in the hinge region whereas high risk HPV16 E2 has a novel alpha-helix NLS in the C domain (Klucevsek et al, 2007; Zou et al, 2000). The HPV11 E1 DNA helicase has a codominant bipartite NLS (Yu et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

Identification of the nuclear localization and export signals of high risk HPV16 E7 oncoprotein

et al. 2009

Self Cite

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The E7 oncoprotein of high risk human papillomavirus type 16 (HPV16) binds and inactivates the retinoblastoma (RB) family of proteins. Our previous studies suggested that HPV16 E7 enters the nucleus via a novel Ran-dependent pathway independent of the nuclear import receptors (Angeline et al., 2003). Here, analysis of the localization of specific E7 mutants revealed that the nuclear localization of E7 is independent of its interaction with pRB or of its phosphorylation by CKII. Fluorescence microscopy analysis of enhanced green fluorescent protein (EGFP) and 2xEGFP fusions with E7 and E7 domains in HeLa cells revealed that E7 contains a novel nuclear localization signal (NLS) in the N-terminal domain (aa 1-37). Interestingly, treatment of transfected HeLa cells with two specific nuclear export inhibitors, Leptomycin B and ratjadone, changed the localization of 2xEGFP-E738-98 from cytoplasmic to mostly nuclear. These data suggest the presence of a leucine-rich nuclear export signal (NES) and a second NLS in the C-terminal domain of E7 (aa 38-98). Mutagenesis of critical amino acids in the putative NES sequence (76IRTLEDLLM84) changed the localization of 2xEGFP-E738-98 from cytoplasmic to mostly nuclear suggesting that this is a functional NES. The presence of both NLSs and an NES suggests that HPV16 E7 shuttles between the cytoplasm and nucleus which is consistent with E7 having functions in both of these cell compartments.

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Characterization of the nuclear localization signal of high risk HPV16 E2 protein

Cited by 14 publications

References 23 publications

Modification of papillomavirus E2 proteins by the small ubiquitin-like modifier family members (SUMOs)

Modification of papillomavirus E2 proteins by the small ubiquitin-like modifier family members (SUMOs)

The Papillomavirus E2 proteins

Identification of the nuclear localization and export signals of high risk HPV16 E7 oncoprotein

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