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Role of flanking sequences and phosphorylation in the recognition of the simian-virus-40 large T-antigen nuclear localization sequences by importin-a

Fontes, Marcos; Teh, Trazel; Toth, Gabor; John, Anna; Pavo, Imre; Jans, David A; Kobe, Bostjan

Description

The nuclear import of simian-virus-40 large T-antigen (tumour antigen) is enhanced via phosphorylation by the protein kinase CK2 at Ser112 in the vicinity of the NLS (nuclear localization sequence). To determine the structural basis of the effect of the sequences flanking the basic cluster KKKRK, and the effect of phosphorylation on the recognition of the NLS by the nuclear import factor importin-α (Impa), we co-crystallized non-autoinhibited Impa with peptides corresponding to the...[Show more]

dc.contributor.authorFontes, Marcos
dc.contributor.authorTeh, Trazel
dc.contributor.authorToth, Gabor
dc.contributor.authorJohn, Anna
dc.contributor.authorPavo, Imre
dc.contributor.authorJans, David A
dc.contributor.authorKobe, Bostjan
dc.date.accessioned2015-12-13T22:31:41Z
dc.date.available2015-12-13T22:31:41Z
dc.identifier.issn0264-6021
dc.identifier.urihttp://hdl.handle.net/1885/75363
dc.description.abstractThe nuclear import of simian-virus-40 large T-antigen (tumour antigen) is enhanced via phosphorylation by the protein kinase CK2 at Ser112 in the vicinity of the NLS (nuclear localization sequence). To determine the structural basis of the effect of the sequences flanking the basic cluster KKKRK, and the effect of phosphorylation on the recognition of the NLS by the nuclear import factor importin-α (Impa), we co-crystallized non-autoinhibited Impa with peptides corresponding to the phosphorylated and non-phosphorylated forms of the NLS, and determined the crystal structures of the complexes. The structures show that the amino acids N-terminally flanking the basic cluster make specific contacts with the receptor that are distinct from the interactions between bipartite NLSs and Impα. We confirm the important role of flanking sequences using binding assays. Unexpectedly, the regions of the peptides containing the phosphorylation site do not make specific contacts with the receptor. Binding assays confirm that phosphorylation does not increase the affinity of the T-antigen NLS to Impα. We conclude that the sequences flanking the basic clusters in NLSs play a crucial role in nuclear import by modulating the recognition of the NLS by Impα, whereas phosphorylation of the T-antigen enhances nuclear import by a mechanism that does not involve a direct interaction of the phosphorylated residue with Impα.
dc.publisherPortland Press
dc.sourceBiochemical Journal
dc.subjectKeywords: Antigens; Bioassay; Crystal structure; Crystallization; Tumors; Viruses; Phosphorylation; Biochemistry; karyopherin alpha; peptide; virus large T antigen; article; binding affinity; binding assay; crystal structure; crystallization; DNA flanking region; m Importin-a (karyopherin-a); Nuclear localization sequence recognition (NLS recognition); Phosphorylation; Simian-virus-40 (SV40) large tumour-antigen nuclear localization sequence; X-ray crystal structure
dc.titleRole of flanking sequences and phosphorylation in the recognition of the simian-virus-40 large T-antigen nuclear localization sequences by importin-a
dc.typeJournal article
local.description.notesImported from ARIES
local.description.refereedYes
local.identifier.citationvolume375
dc.date.issued2003
local.identifier.absfor110199 - Medical Biochemistry and Metabolomics not elsewhere classified
local.identifier.ariespublicationMigratedxPub4588
local.type.statusPublished Version
local.contributor.affiliationFontes, Marcos, University of Queensland
local.contributor.affiliationTeh, Trazel, St Vincent's Institute of Medical Research
local.contributor.affiliationToth, Gabor, Szeged Medical University
local.contributor.affiliationJohn, Anna, College of Medicine, Biology and Environment, ANU
local.contributor.affiliationPavo, Imre, Szeged Medical University
local.contributor.affiliationJans, David A, College of Medicine, Biology and Environment, ANU
local.contributor.affiliationKobe, Bostjan, St Vincent's Institute of Medical Research
local.bibliographicCitation.startpage339
local.bibliographicCitation.lastpage349
local.identifier.doi10.1042/BJ20030510
dc.date.updated2015-12-11T09:02:05Z
local.identifier.scopusID2-s2.0-0142231575
CollectionsANU Research Publications

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