Structural and calorimetric studies demonstrate that Xeroderma pigmentosum type G (XPG) can be imported to the nucleus by a classical nuclear import pathway via a monopartite NLS sequence

de Barros, Andrea C., Takeda, Agnes A.S., Dreyer, Thiago R., Velazquez-Campoy, Adrian, Kobe, Bostjan and Fontes, Marcos R.M. (2016) Structural and calorimetric studies demonstrate that Xeroderma pigmentosum type G (XPG) can be imported to the nucleus by a classical nuclear import pathway via a monopartite NLS sequence. Journal of Molecular Biology, 428 10: 2120-2131. doi:10.1016/j.jmb.2016.01.019


Author de Barros, Andrea C.
Takeda, Agnes A.S.
Dreyer, Thiago R.
Velazquez-Campoy, Adrian
Kobe, Bostjan
Fontes, Marcos R.M.
Title Structural and calorimetric studies demonstrate that Xeroderma pigmentosum type G (XPG) can be imported to the nucleus by a classical nuclear import pathway via a monopartite NLS sequence
Journal name Journal of Molecular Biology   Check publisher's open access policy
ISSN 1089-8638
0022-2836
Publication date 2016-05-22
Year available 2016
Sub-type Article (original research)
DOI 10.1016/j.jmb.2016.01.019
Open Access Status Not Open Access
Volume 428
Issue 10
Start page 2120
End page 2131
Total pages 12
Place of publication London, United Kingdom
Publisher Academic Press
Collection year 2017
Language eng
Formatted abstract
Xeroderma pigmentosum type G (XPG) proteins are involved in DNA lesion recognition and promotion of nucleotide excision repair. Specific mutations in these proteins may lead to Cockayne syndrome, in which the patients may display severe developmental retardation and neurological abnormalities. No structural information is available for their spacer region or the C-terminal domain, which are important, respectively, for specific nucleotide excision repair activity and substrate specificity, as well as nuclear translocation. Immunofluorescence studies suggested two specific regions of the XPG C-terminus as potential bipartite nuclear localization sequences, which would be responsible for its translocation to the nucleus by the classical nuclear import pathway mediated by the importin‐α (Impα). Thus, in order to test these hypotheses and gain insight into the structural basis for the nuclear import process for the XPG protein, we solved the crystal structures of complexes formed by the Impα and peptides corresponding to both putative nuclear localization signal (NLS) sequences (XPG1 and XPG2) and performed isothermal titration calorimetry assays to determine their binding affinities. Structural experiments confirm the binding of both NLS peptides to Impα but, unexpectedly, they bind to the receptor as monopartite NLSs. The isothermal titration calorimetry assays demonstrated that XPG1 and XPG2 peptides bind to two separate binding sites, but with high affinity to the major NLS-binding site of the Impα, resembling classical monopartite SV40 TAg NLS. The results lead to insights about what distinguishes monopartite and bipartite NLSs, as well as the differential roles of XPG1 and XPG2 NLSs in the nuclear localization of XPG.
Keyword Importin α
Xeroderma pigmentosum protein
Nuclear localization sequence (NLS)
DNA repair proteins
Nucleotide excision repair
X-ray crystallography
XPG protein
Isothermal titration calorimetry
Nuclear import pathway
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
School of Chemistry and Molecular Biosciences
Institute for Molecular Bioscience - Publications
 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 0 times in Thomson Reuters Web of Science Article
Scopus Citation Count Cited 2 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Fri, 29 Jan 2016, 13:44:35 EST by Mrs Louise Nimwegen on behalf of School of Chemistry & Molecular Biosciences