Dataset Information

Evidence for changes in beta- and gamma-actin proportions during inner ear hair cell life.

ABSTRACT: Cytoplasmic actin isoforms beta (?-) and gamma (?-) perform crucial physiological roles in inner ear hair cells (HC). The stereocilium, which is structured by parallel actin filaments composed of both isoforms, is the responsive organelle to mechanical stimuli such as sound, gravity and head movements. Modifications in isoform proportions affect the function of the stereocilia as previously shown in genetic studies of mutant mice. Here, immunogold labeling TEM studies in mice showed that both ?- and ?-actin isoforms colocalize throughout stereocilia actin filaments, adherens junctions and cuticular plates as early as embryonic stage 16.5. Gold-particle quantification indicated that there was 40% more ?- actin than ?-actin at E16.5. In contrast, ?- and ?-actin were equally concentrated in adult stereocilia of cochlear and vestibular HC. Interestingly, all actin-based structures presented almost five-fold more ?-actin than ?-actin in 22 month- old mice, suggesting that ?-actin is probably under-expressed during the aging process. These data provide evidence of dynamic modifications of the actin isoforms in stereocilia, cuticular plates and cell junctions during the whole HC life.

SUBMITTER: Andrade LR

PROVIDER: S-EPMC4529820 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Evidence for changes in beta- and gamma-actin proportions during inner ear hair cell life.

Andrade Leonardo R LR

Cytoskeleton (Hoboken, N.J.) 20150630 6

Cytoplasmic actin isoforms beta (β-) and gamma (γ-) perform crucial physiological roles in inner ear hair cells (HC). The stereocilium, which is structured by parallel actin filaments composed of both isoforms, is the responsive organelle to mechanical stimuli such as sound, gravity and head movements. Modifications in isoform proportions affect the function of the stereocilia as previously shown in genetic studies of mutant mice. Here, immunogold labeling TEM studies in mice showed that both β- ...[more]

PMID: 26033950

Similar Datasets

Project description:The mammalian inner ear (IE) subserves auditory and vestibular sensations via highly specialized cells and proteins. Sensory receptor hair cells (HCs) are necessary for transducing mechanical inputs and stimulating sensory neurons by using a host of known and as yet unknown protein machinery. To understand the protein composition of these unique postmitotic cells, in which irreversible protein degradation or damage can lead to impaired hearing and balance, we analyzed IE samples by tandem mass spectrometry to generate an unbiased, shotgun-proteomics view of protein identities and abundances. By using Pou4f3/eGFP-transgenic mice in which HCs express GFP driven by Pou4f3, we FACS purified a population of HCs to analyze and compare the HC proteome with other IE subproteomes from sensory epithelia and whole IE. We show that the mammalian HC proteome comprises hundreds of uniquely or highly expressed proteins. Our global proteomic analysis of purified HCs extends the existing HC transcriptome, revealing previously undetected gene products and isoform-specific protein expression. Comparison of our proteomic data with mouse and human databases of genetic auditory/vestibular impairments confirms the critical role of the HC proteome for normal IE function, providing a cell-specific pool of candidates for novel, important HC genes. Several proteins identified exclusively in HCs by proteomics and verified by immunohistochemistry map to human genetic deafness loci, potentially representing new deafness genes. SIGNIFICANCE STATEMENT:Hearing and balance rely on specialized sensory hair cells (HCs) in the inner ear (IE) to convey information about sound, acceleration, and orientation to the brain. Genetically and environmentally induced perturbations to HC proteins can result in deafness and severe imbalance. We used transgenic mice with GFP-expressing HCs, coupled with FACS sorting and tandem mass spectrometry, to define the most complete HC and IE proteome to date. We show that hundreds of proteins are uniquely identified or enriched in HCs, extending previous gene expression analyses to reveal novel HC proteins and isoforms. Importantly, deafness-linked proteins were significantly enriched in HCs, suggesting that this in-depth proteomic analysis of IE sensory cells may hold potential for deafness gene discovery.

Dataset Information

Evidence for changes in beta- and gamma-actin proportions during inner ear hair cell life.

Publications

Evidence for changes in beta- and gamma-actin proportions during inner ear hair cell life.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets