γ-Actin is required for cytoskeletal maintenance but not development

Inna A. Belyantseva, Benjamin J. Perrin, Kevin J. Sonnemann, Mei Zhu, Ruben Stepanyan, Joann McGee, Gregory I. Frolenkov, Edward J. Walsh, Karen H. Friderici, Thomas B. Friedman, James M. Ervasti

Research output: Contribution to journalArticlepeer-review

104 Scopus citations

Abstract

βcyto-Actin and γcyto-actin are ubiquitous proteins thought to be essential building blocks of the cytoskeleton in all non-muscle cells. Despite this widely held supposition, we show that γcyto-actin null mice (Actg1-/-) are viable. However, they suffer increased mortality and show progressive hearing loss during adulthood despite compensatory up-regulation of βcyto- actin. The surprising viability and normal hearing of young Actg1-/- mice means that βcyto-actin can likely build all essential non-muscle actin-based cytoskeletal structures including mechanosensory stereocilia of hair cells that are necessary for hearing. Although γcyto-actin-deficient stereocilia form normally, we found that they cannot maintain the integrity of the stereocilia actin core. In the wild-type, γcyto-actin localizes along the length of stereocilia but re-distributes to sites of F-actin core disruptions resulting from animal exposure to damaging noise. In Actg1-/- stereocilia similar disruptions are observed even without noise exposure. We conclude that γcyto-actin is required for reinforcement and long-term stability of F-actin-based structures but is not an essential building block of the developing cytoskeleton.

Original languageEnglish (US)
Pages (from-to)9703-9708
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume106
Issue number24
DOIs
StatePublished - Jun 16 2009

Keywords

  • Actin
  • Cytoskeleton
  • Hearing

ASJC Scopus subject areas

  • General

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