Actin binding to WH2 domains regulates nuclear import of the multifunctional actin regulator JMY

Research output: Contribution to journalArticle

Authors

External Institution(s)

  • University of California at San Francisco
  • The University of Chicago

Details

Original languageEnglish (US)
Pages (from-to)853-863
Number of pages11
JournalMolecular biology of the cell
Volume23
Issue number5
StatusPublished - Mar 1 2012
Peer-reviewedYes

Abstract

Junction-mediating and regulatory protein (JMY) is a regulator of both transcription and actin filament assembly. In response to DNA damage, JMY accumulates in the nucleus and promotes p53-dependent apoptosis. JMY's actin-regulatory activity relies on a cluster of three actin-binding Wiskott-Aldrich syndrome protein homology 2 (WH2) domains that nucleate filaments directly and also promote nucleation activity of the Arp2/3 complex. In addition to these activities, we find that the WH2 cluster overlaps an atypical, bipartite nuclear localization sequence (NLS) and controls JMY's subcellular localization. Actin monomers bound to the WH2 domains block binding of importins to the NLS and prevent nuclear import of JMY. Mutations that impair actin binding, or cellular perturbations that induce actin filament assembly and decrease the concentration of monomeric actin in the cytoplasm, cause JMY to accumulate in the nucleus. DNA damage induces both cytoplasmic actin polymerization and nuclear import of JMY, and we find that damage-induced nuclear localization of JMY requires both the WH2/NLS region and importin &βετα;. On the basis of our results, we propose that actin assembly regulates nuclear import of JMY in response to DNA damage.

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