The Stereociliary Paracrystal Is a Dynamic Cytoskeletal Scaffold In Vivo

• DOI: 10.1016/j.celrep.2015.10.003
• Publication Date: 2015-11-05T12:14:06Z
• Authors: Philsang Hwang; Shih-Wei Chou; Zongwei Chen; Brian M. McDermott
• Keywords: 0303 health sciences; QH301-705.5; Microfilament Proteins; Myosins; Zebrafish Proteins; Stereocilia; Protein Transport; 03 medical and health sciences; Hair Cells, Auditory; Animals; Biology (General); Eye Proteins; Cytoskeleton; Zebrafish

Permanency of mechanosensory stereocilia may be the consequence low protein turnover or rapid renewal. Here, we devise a system, using optical techniques in live zebrafish, to distinguish between these mechanisms. We demonstrate that stereocilium's abundant actin cross-linker fascin 2b exchanges, without bias phosphointermediate, orders magnitude faster (t1/2 76.3 s) than any other known hair bundle protein. To establish logic 2b's exchange, examine whether filamentous is dynamic and detect substantial β-actin exchange within paracrystal 4.08 hr). propose behavior enable cross-linking at fast timescales vibration while noninstructively facilitating slower process exchange. Furthermore, tip myosin XVa fully exchanges hours 11.6 hr), indicating delivery myosin-associated cargo occurs mature stereocilia. These findings suggest permanency underpinned by vibrant