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Identification of a Nuclear Localization Sequence in Beta-Arrestin1:Implications in NF- kB Activation

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posted on 15.04.2014 by Crystal Z. Hoeppner
A mounting body of evidence suggests that beta-arrestin1 plays important roles in the nucleus, but how beta-arrestin1 enters the nucleus remains unclear since no nuclear import signal has been identified in the -arrestins. We sought to characterize the cellular localization of wild type beta-arrestin1 and a series of N domain mutants to determine the structural basis and functional implications of beta-arrestin1 nuclear localization. A seven-residue candidate nuclear localization sequence (NLS) was identified based on sequence analysis. Mutation of the NLS led to a loss of beta-arrestin1 nuclear localization in transfected cells. Exogenous expression of wild type beta-arrestin1 enhanced the transcriptional activity of nuclear factor kappaB (NF-kappaB) induced by bradykinin, while mutation of the NLS reduced this effect by two thirds relative to wild type controls. Loss of beta-arrestin1 nuclear localization was accompanied by reduced recruitment of the CREB binding protein and altered post-translational modification profile of p65/RelA. Further mutational analysis identified Lys157 within the putative NLS as being critical to nuclear localization of beta-arrestin1. Substitution of Lys157 to Ala led to reduced nuclear localization, decreased promoter binding by p65/RelA and decreased IL-1beta gene transcription. These results demonstrate a critical role for beta-arrestin1 nuclear localization in scaffolding and transcriptional regulation.

History

Advisor

Ye, Richard D.

Department

Pharmacology

Degree Grantor

University of Illinois at Chicago

Degree Level

Doctoral

Committee Member

Skidgel, Randal A. Christman, John W. O'Bryan, John P. Colamonici, Oscar

Submitted date

2012-05

Language

en

Issue date

10/12/2012

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