The L1 major capsid protein of human papillomavirus type 11 interacts with kap β2 and kap β3 nuclear import receptors

Nelson, Lisa M.; Rose, Robert C.; Moroianu, Junona

doi:10.1016/s0042-6822(02)00025-9

Cited by 23 publications

(22 citation statements)

References 43 publications

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“…1 and 2). Utilization of the ␣/␤ transport pathway by E1 is consistent with previous observations that several other papillomavirus proteins, including L1 (HPV11, HPV16, and HPV45), L2 (HPV16), and E6 (HPV16), also enter the nucleus via the importin ␣1/␤1 pathway (11,32,39,(41)(42)(43). In addition, we found that HPV11 and HPV16 E2 proteins, which both contain a well-characterized NLS (4,55,67), also displayed in vitro binding to importins ␣3 and ␣5 (unpublished data).…”

Section: Discussionsupporting

confidence: 91%

Nuclear Import of Bovine Papillomavirus Type 1 E1 Protein Is Mediated by Multiple Alpha Importins and Is Negatively Regulated by Phosphorylation near a Nuclear Localization Signal

Bian

Rosas-Acosta

et al. 2007

J Virol

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Papillomavirus DNA replication occurs in the nucleus of infected cells and requires the viral E1 protein, which enters the nuclei of host epithelial cells and carries out enzymatic functions required for the initiation of viral DNA replication. In this study, we investigated the pathway and regulation of the nuclear import of the E1 protein from bovine papillomavirus type 1 (BPV1). Using an in vitro binding assay, we determined that the E1 protein interacted with importins ␣3, ␣4, and ␣5 via its nuclear localization signal (NLS) sequence. In agreement with this result, purified E1 protein was effectively imported into the nucleus of digitonin-permeabilized HeLa cells after incubation with importin ␣3, ␣4, or ␣5 and other necessary import factors. We also observed that in vitro binding of E1 protein to all three ␣ importins was significantly decreased by the introduction of pseudophosphorylation mutations in the NLS region. Consistent with the binding defect, pseudophosphorylated E1 protein failed to enter the nucleus of digitonin-permeabilized HeLa cells in vitro. Likewise, the pseudophosphorylation mutant showed aberrant intracellular localization in vivo and accumulated primarily on the nuclear envelope in transfected HeLa cells, while the corresponding alanine replacement mutant displayed the same cellular location pattern as wild-type E1 protein. Collectively, our data demonstrate that BPV1 E1 protein can be transported into the nucleus by more than one importin ␣ and suggest that E1 phosphorylation by host cell kinases plays a regulatory role in modulating E1 nucleocytoplasmic localization. This phosphoregulation of nuclear E1 protein uptake may contribute to the coordination of viral replication with keratinocyte proliferation and differentiation.Papillomaviruses are the etiological agents involved in several human cancers such as cervical cancer, anogenital cancer, skin cancer, and cancers of the oral cavity, the larynx, and the esophagus (68). In addition to their importance in clinical disease, papillomaviruses have provided a valuable model system for analyzing the mechanisms regulating eukaryotic DNA replication. The viral E1 protein is the largest open reading frame and is highly conserved among all papillomaviruses, maintaining its size, amino acid composition, and location in the viral genome with respect to other early genes. The E1 protein is expressed during the early stage of virus infection in order to maintain the viral DNA as an episome. The multifunctional E1 protein recognizes and binds to the viral origin of replication in combination with the viral protein E2, recruits host cell replication proteins to the origin, and initiates DNA replication via its ATP-dependent helicase activity (60, 61).Papillomavirus infection is established in the basal layer of the epithelium, and the complex viral life cycle is coordinated with the differentiation state of the epithelium (13, 14). There are three distinct modes of viral DNA replication: (i) transient amplification, which occurs immediately upon ...

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Section: Discussionsupporting

confidence: 91%

Nuclear Import of Bovine Papillomavirus Type 1 E1 Protein Is Mediated by Multiple Alpha Importins and Is Negatively Regulated by Phosphorylation near a Nuclear Localization Signal

Bian

Rosas-Acosta

et al. 2007

J Virol

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“…The restricted localization of importin beta 3 protein to the elongating spermatids in the adult testis supports this concept, conceivably representing a mechanism for effecting translational regulation in postmeiotic male germ cells. Importin beta 3 (also named Ran BP5) has been implicated in nuclear transport of ribosomal proteins [30,31] as well as of certain transcription factors and viral proteins [32,33]. The abundance of importin beta family members appears to provide some degree of functional redundancy, as illustrated by the ability of importins beta 1, 2, 3, and 7 all to mediate nuclear transport of the ribosomal protein L23a, at least in vitro [31].…”

Section: Discussionmentioning

confidence: 99%

Expression of Nuclear Transport Importins beta 1 and beta 3 Is Regulated During Rodent Spermatogenesis1

Loveland

Hogarth

Szczepny

et al. 2006

Biology of Reproduction

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Spermatogenic differentiation requires progressive gene expression changes, and proteins required for this must be transported into the nucleus. Many of these contain a nuclear localization signal and are likely to be transported by importin protein family members, each of which recognizes and transports distinct cargo proteins. We hypothesized that importins, as modulators of protein nuclear access, would display distinct expression profiles during spermatogenesis, indicating their potential to regulate key steps in cellular differentiation. This was tested throughout testicular development in rodents. Real-time PCR analysis of postnatal mouse testes revealed changing expression levels of Knpb1 (encoding importin beta 1) and Ranbp5 (encoding beta 3) mRNAs, with Knpb1 highest at 26 days postpartum and Ranbp5 highest in Day 26 and adult testis. Their distinctive cellular expression patterns visualized using in situ hybridization and immunohistochemistry were identical in mouse and rat testes where examined. Within the seminiferous epithelium, Knpb1 mRNA and importin beta1 protein were detected within mitotic Sertoli and germ cells during fetal and early postnatal development, becoming restricted to spermatogonia and spermatocytes in adulthood. Importin beta 3 protein in fetal germ cells displayed a striking difference in intracellular localization between male and female gonads. In adult testes, Ranbp5 mRNA was detected in round spermatids and importin beta 3 protein in elongating spermatids. This is the first comprehensive in situ demonstration of developmentally regulated synthesis of nuclear transport components. The contrasting expression patterns of importins beta 1 and 3 identify them as candidates for regulating nuclear access of factors required for developmental switches.

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“…In addition, RanBP5 has been shown to interact with proteins from a range of viruses (Arnold et al, 2006;Chung et al, 2000;Darshan et al, 2004;Deng et al, 2006;Klucevsek et al, 2006;Krawczyk et al, 2008;Nelson et al, 2003). In influenza A virus, RanBP5 could be displaced from PB1 or the PB1 : PA dimer by the addition of non-hydrolysable RanGTP in vitro, and depletion of RanBP5 reduced the nuclear accumulation of PB1 and of PB1 : PA.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the interaction between the influenza A virus polymerase subunit PB1 and the host nuclear import factor Ran-binding protein 5

Hutchinson

Orr

Liu

et al. 2011

Journal of General Virology

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The influenza A virus RNA polymerase is a heterotrimer that transcribes and replicates the viral genome in the cell nucleus. Newly synthesized RNA polymerase subunits must therefore be imported into the nucleus during an infection. While various models have been proposed for this process, the consensus is that the polymerase basic protein PB1 and polymerase acidic protein PA subunits form a dimer in the cytoplasm and are transported into the nucleus by the betaimportin Ran-binding protein 5 (RanBP5), with the PB2 subunit imported separately to complete the trimeric complex. In this study, we characterized the interaction of PB1 with RanBP5 further and assessed its importance for viral growth. In particular, we found that the N-terminal region of PB1 mediates its binding to RanBP5 and that basic residues in a nuclear localization signal are required for RanBP5 binding. Mutating these basic residues to alanines does not prevent PB1 forming a dimer with PA, but does reduce RanBP5 binding. RanBP5-binding mutations reduce, though do not entirely prevent, the nuclear accumulation of PB1. Furthermore, mutations affecting RanBP5 binding are incompatible with or severely attenuate viral growth, providing further support for a key role for RanBP5 in the influenza A virus life cycle. INTRODUCTIONInfluenza A virus is the prototypic orthomyxovirus and a serious pathogen of humans and animals. The viral genome consists of eight segments of negative-sense, ssRNA, which are encapsidated as viral ribonucleoprotein complexes (vRNPs) by multiple copies of nucleoprotein (NP) and the trimeric RNA-dependent RNA polymerase (RdRP; consisting of the polymerase basic proteins PB1 and PB2, and the polymerase acidic protein PA) (Palese & Shaw, 2007). Unusually among RNA viruses, orthomyxoviruses replicate their genomes in the nucleus. Consequently, newly synthesized viral proteins must be imported into the nucleus to allow the assembly and export of new vRNPs, as well as to regulate host processes in the infected cell. Of the proteins expressed by influenza A virus, nuclear import is observed for the three polymerase proteins and NP, as well as matrix (M1) protein, non-structural (NS1) protein, nuclear export protein (NEP) and PB1-F2 (Chen et al., 2001;Smith et al., 1987). Nuclear import of structures larger than 20-30 kDa is selective and energy dependent, requiring binding of nuclear import factors (NIFs) through nuclear localization signals (NLSs) on import substrates (Görlich & Kutay, 1999). A number of influenza A virus proteins have been shown to contain NLSs and to bind NIFs Naito et al., 2007; Resa-Infante et al., 2008;Tarendeau et al., 2007). PB1 and PA, despite both having signals that can promote nuclear import when individually expressed (Akkina et al., 1987;Nath & Nayak, 1990;Nieto et al., 1994), do not accumulate efficiently in the nucleus unless expressed together, a requirement that appears to be particularly marked for PB1 (Fodor & Smith, 2004;Huet et al., 2010;Nieto et al., 1992). Although all possible pairwise interact...

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The L1 major capsid protein of human papillomavirus type 11 interacts with kap β2 and kap β3 nuclear import receptors

Cited by 23 publications

References 43 publications

Nuclear Import of Bovine Papillomavirus Type 1 E1 Protein Is Mediated by Multiple Alpha Importins and Is Negatively Regulated by Phosphorylation near a Nuclear Localization Signal

Nuclear Import of Bovine Papillomavirus Type 1 E1 Protein Is Mediated by Multiple Alpha Importins and Is Negatively Regulated by Phosphorylation near a Nuclear Localization Signal

Expression of Nuclear Transport Importins beta 1 and beta 3 Is Regulated During Rodent Spermatogenesis1

Characterization of the interaction between the influenza A virus polymerase subunit PB1 and the host nuclear import factor Ran-binding protein 5

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