PUBLICATION

Fascin 2b Is a Component of Stereocilia that Lengthens Actin-Based Protrusions

Authors
Chou, S.W., Hwang, P., Gomez, G., Fernando, C.A., West, M.C., Pollock, L.M., Lin-Jones, J., Burnside, B., and McDermott, B.M.
ID
ZDB-PUB-110609-32
Date
2011
Source
PLoS One   6(4): e14807 (Journal)
Registered Authors
Burnside, Beth, Chou, Shih-wei, Fernando, Carol, Gomez, Gustavo, Hwang, Philsang, Lin-Jones, Jennifer, McDermott Jr., Brian M., Pollock, Lana, West, Megan
Keywords
none
MeSH Terms
  • Actins/metabolism*
  • Animals
  • Animals, Genetically Modified
  • COS Cells
  • Chlorocebus aethiops
  • Cilia/metabolism*
  • Eye Proteins/chemistry
  • Eye Proteins/genetics
  • Eye Proteins/metabolism*
  • Hair Cells, Auditory/cytology
  • Hair Cells, Auditory/metabolism
  • Microfilament Proteins/chemistry
  • Microfilament Proteins/genetics
  • Microfilament Proteins/metabolism*
  • Mutagenesis, Site-Directed
  • Mutation
  • Phosphoproteins/chemistry
  • Phosphoproteins/genetics
  • Phosphoproteins/metabolism
  • Phosphorylation
  • Protein Transport
  • Pseudopodia/metabolism
  • RNA, Messenger/genetics
  • RNA, Messenger/metabolism
  • Serine
  • Zebrafish/genetics
PubMed
21625653 Full text @ PLoS One
Abstract
Stereocilia are actin-filled protrusions that permit mechanotransduction in the internal ear. To identify proteins that organize the cytoskeleton of stereocilia, we scrutinized the hair-cell transcriptome of zebrafish. One promising candidate encodes fascin 2b, a filamentous actin-bundling protein found in retinal photoreceptors. Immunolabeling of zebrafish hair cells and the use of transgenic zebrafish that expressed fascin 2b fused to green fluorescent protein demonstrated that fascin 2b localized to stereocilia specifically. When filamentous actin and recombinant fusion protein containing fascin 2b were combined in vitro to determine their dissociation constant, a K(d)H0.37 ┬ÁM was observed. Electron microscopy showed that fascin 2b-actin filament complexes formed parallel actin bundles in vitro. We demonstrated that expression of fascin 2b or espin, another actin-bundling protein, in COS-7 cells induced the formation of long filopodia. Coexpression showed synergism between these proteins through the formation of extra-long protrusions. Using phosphomutant fascin 2b proteins, which mimicked either a phosphorylated or a nonphosphorylated state, in COS-7 cells and in transgenic hair cells, we showed that both formation of long filopodia and localization of fascin 2b to stereocilia were dependent on serine 38. Overexpression of wild-type fascin 2b in hair cells was correlated with increased stereociliary length relative to controls. These findings indicate that fascin 2b plays a key role in shaping stereocilia.
Genes / Markers
Figures
Figure Gallery
Expression
Phenotype
Mutation and Transgenics
Human Disease / Model Data
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping
Errata and Notes