Importin β-dependent nuclear import of TopBP1 in ATR-Chk1 checkpoint in Xenopus egg extracts.

ABSTRACT: TopBP1, a multiple-BRCT-containing protein, plays diverse functions in DNA metabolism including DNA replication, DNA damage response and transcriptional regulation. The cytoplasmic localization of TopBP1 has been found to be associated with breast cancer susceptibility in clinical studies, suggesting the biological significance of TopBP1's sub-cellular localization. However, it remains elusive how TopBP1 is shuttled into nucleus and recruited to chromatin under normal or stressful conditions. Taking advantage of Xenopus egg extract, we identified Importin β as a new interacting protein of the TopBP1 C-terminus. We verified the TopBP1-Importin β association via GST pulldown and coimmunoprecipitation assays. We then demonstrated that TopBP1's C-terminal motif (designated as CTM, 23 amino aci

SUBMITTER: Bai L 

PROVIDER: S-EPMC3951582 | biostudies-literature | 2014 May

REPOSITORIES: biostudies-literature