|ZFIN ID: ZDB-PUB-151110-7|
The Stereociliary Paracrystal Is a Dynamic Cytoskeletal Scaffold In Vivo
Hwang, P., Chou, S.W., Chen, Z., McDermott, B.M.
|Source:||Cell Reports 13(7): 1287-94 (Journal)|
|Registered Authors:||Chou, Shih-wei, Hwang, Philsang, McDermott Jr., Brian M.|
|PubMed:||26549442 Full text @ Cell Rep.|
Hwang, P., Chou, S.W., Chen, Z., McDermott, B.M. (2015) The Stereociliary Paracrystal Is a Dynamic Cytoskeletal Scaffold In Vivo. Cell Reports. 13(7):1287-94.
ABSTRACTPermanency of mechanosensory stereocilia may be the consequence of low protein turnover or rapid protein renewal. Here, we devise a system, using optical techniques in live zebrafish, to distinguish between these mechanisms. We demonstrate that the stereocilium's abundant actin cross-linker fascin 2b exchanges, without bias or a phosphointermediate, orders of magnitude faster (t1/2 of 76.3 s) than any other known hair bundle protein. To establish the logic of fascin 2b's exchange, we examine whether filamentous actin is dynamic and detect substantial β-actin exchange within the stereocilium's paracrystal (t1/2 of 4.08 hr). We propose that fascin 2b's behavior may enable cross-linking at fast timescales of stereocilia vibration while noninstructively facilitating the slower process of actin exchange. Furthermore, tip protein myosin XVa fully exchanges in hours (t1/2 of 11.6 hr), indicating that delivery of myosin-associated cargo occurs in mature stereocilia. These findings suggest that stereocilia permanency is underpinned by vibrant protein exchange.