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 (TriobpΔex8/Δex8) that are profoundly deaf. Stereocilia of TriobpΔex8/Δex8 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.
| Original language | English |
|---|---|
| Pages (from-to) | 786-798 |
| Number of pages | 13 |
| Journal | Cell |
| Volume | 141 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 2010 |
Bibliographical note
Funding Information:The authors thank M. Ikeya for advice and vectors, M. Streuli for mononclonal antiserum to TRIOBP-1/5, P. Belyantsev for drawings, and N. Gavara, M. Barzik, R. Chadwick, J. Schultz, and D. Drayna for discussions. This work was supported by NIDCD/NIH R01DC008861 and R01DC009434 to G.I.F., R01 DC004314 to J.R.B., the Wellcome Trust grant 071394/Z/03/Z to G.P.R., the HEC and MoST, Islamabad to S.R., intramural programs of NIDDK, NHLBI, and NIDCD Z01 DK060100 to J.E.H., Z01 DK060100 to J.A.H., Z01 HL004232-08 to J.S., Z01 DC 000064 to A.J.G., and Z01 DC000048 to T.B.F.
Funding
The authors thank M. Ikeya for advice and vectors, M. Streuli for mononclonal antiserum to TRIOBP-1/5, P. Belyantsev for drawings, and N. Gavara, M. Barzik, R. Chadwick, J. Schultz, and D. Drayna for discussions. This work was supported by NIDCD/NIH R01DC008861 and R01DC009434 to G.I.F., R01 DC004314 to J.R.B., the Wellcome Trust grant 071394/Z/03/Z to G.P.R., the HEC and MoST, Islamabad to S.R., intramural programs of NIDDK, NHLBI, and NIDCD Z01 DK060100 to J.E.H., Z01 DK060100 to J.A.H., Z01 HL004232-08 to J.S., Z01 DC 000064 to A.J.G., and Z01 DC000048 to T.B.F.
| Funders | Funder number |
|---|---|
| Ministry of Science and Technology, Taiwan | |
| National Institute of Diabetes and Digestive and Kidney Diseases | |
| Higher Education Commission, Pakistan | |
| National Institute on Deafness and Other Communication Disorders | ZIADC000060, ZIADC000048, ZIADC000039 |
| National Heart, Lung, and Blood Institute (NHLBI) | Z01 DC 000064, ZIAHL006120, ZIAHL004232, Z01 DK060100 |
| Wellcome Trust | 071394, 071394/Z/03/Z |
| National Institutes of Health (NIH) | R01 DC004314, R01DC008861, R01DC009434 |
Keywords
- Cellbio
- Humdisease
- Molneuro
ASJC Scopus subject areas
- General Biochemistry, Genetics and Molecular Biology