| Literature DB >> 20510926 |
Shin-ichiro Kitajiri1, Takeshi Sakamoto, Inna A Belyantseva, Richard J Goodyear, Ruben Stepanyan, Ikuko Fujiwara, Jonathan E Bird, Saima Riazuddin, Sheikh Riazuddin, Zubair M Ahmed, Jenny E Hinshaw, James Sellers, James R Bartles, John A Hammer, Guy P Richardson, Andrew J Griffith, Gregory I Frolenkov, Thomas B Friedman.
Abstract
Inner ear hair cells detect sound through deflection of mechanosensory stereocilia. Each stereocilium is supported by a paracrystalline array of parallel actin filaments that are packed more densely at the base, forming a rootlet extending into the cell body. The function of rootlets and the molecules responsible for their formation are unknown. We found that TRIOBP, a cytoskeleton-associated protein mutated in human hereditary deafness DFNB28, is localized to rootlets. In vitro, purified TRIOBP isoform 4 protein organizes actin filaments into uniquely dense bundles reminiscent of rootlets but distinct from bundles formed by espin, an actin crosslinker in stereocilia. We generated mutant Triobp mice (Triobp(Deltaex8/Deltaex8)) that are profoundly deaf. Stereocilia of Triobp(Deltaex8/Deltaex8) mice develop normally but fail to form rootlets and are easier to deflect and damage. Thus, F-actin bundling by TRIOBP provides durability and rigidity for normal mechanosensitivity of stereocilia and may contribute to resilient cytoskeletal structures elsewhere. Copyright 2010 Elsevier Inc. All rights reserved.Entities:
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Year: 2010 PMID： 20510926 PMCID： PMC2879707 DOI： 10.1016/j.cell.2010.03.049
Source DB: PubMed Journal: Cell ISSN： 0092-8674 Impact factor: 41.582