The R109H Variant of Fascin-2, a Developmentally Regulated Actin Crosslinker in Hair-Cell Stereocilia, Underlies Early-Onset Hearing Loss of DBA/2J Mice

Shin, Jung Bum; Longo-Guess, Chantal M.; Gagnon, Leona H.; Saylor, Katherine W.; Dumont, Rachel A.; Spinelli, Kateri J.; Pagana, James M.; Wilmarth, Phillip A.; David, Larry L.; Gillespie, Peter G.; Johnson, Kenneth R.

doi:10.1523/jneurosci.1541-10.2010

Cited by 112 publications

(177 citation statements)

References 44 publications

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“…A point mutation in Drosophila fascin (the singed mutant) in Gly 409 (to Glu) (equivalent to Gly 393 in human fascin 1, next to the critical His 392 in actin-binding site 1) reduced fascin activity in vivo, implying that this actin-binding site 1 is functionally critical (40). Furthermore, a point mutation of Arg 109 to His in fascin-2 (corresponding to Arg 110 in fascin-1 in the actinbinding site 2) led to early-onset hearing loss in mice (fascin-2 is the main actin-bundling protein in hair-cell stereocilia) (41). Also, fascin(K22E/K43E/R398E) and fascin(R271E/K353E/ K358E) mutants had been shown to be defective in actin bundling (24).…”

Section: Discussionmentioning

confidence: 99%

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Molecular Mechanism of Fascin Function in Filopodial Formation

Yang

Huang

et al. 2013

Journal of Biological Chemistry

112

172

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Background:Fascin is the main actin-bundling protein in filopodia. Results: Biochemical, cryo-electron tomographic, and x-ray crystal structural data reveal the unique actin-binding characteristics of fascin. Conclusion: There are two major actin-binding sites on fascin and there is a concerted conformational change between the actin-binding sites. Significance: These data will advance our understanding of the function of fascin in filopodial formation.

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Section: Discussionmentioning

confidence: 99%

“…In addition to the above conformational changes in ␤-trefoil fold 2, these individual mutations had effects on their local environment. In fascin(S39D), the introduction of a negative charged residue changed the orientation of the side chain of the positively charged residue Lys 41 , which is critical for actin bundling (Fig. 5, A-C, and Table 1).…”

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confidence: 99%

Molecular Mechanism of Fascin Function in Filopodial Formation

Yang

Huang

et al. 2013

Journal of Biological Chemistry

112

172

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“…On Chr 11, a LOD score of 3.15 (p=0.0193) was detected at 92.9 cM near marker D11Mit126 using 16, 24, and 32 kHz. Also located near D11Mit126 is the ahl8 QTL identified as Fscn2 (fascin homologue 2, actin-bundling protein, retinal) (Shin et al 2010). Given that ahl8 is associated with a G-to-A transition (G326A, rs26996001) in Fscn2, we sequenced this nucleotide in 129S6 versus CBACa as previously described (Shin et al 2010) and determined that both strains carry the wildtype G326A allele (data not shown).…”

Section: S6 Crossmentioning

confidence: 96%

Resistance to Noise-Induced Hearing Loss in 129S6 and MOLF Mice: Identification of Independent, Overlapping, and Interacting Chromosomal Regions

Street

Kujawa

Manichaikul

et al. 2014

JARO

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Noise-induced hearing loss (NIHL) is a prevalent health risk. Inbred mouse strains 129S6/SvEvTac (129S6) and MOLF/EiJ (MOLF) show strong NIHL resistance (NR) relative to CBA/CaJ (CBACa). In this study, we developed quantitative trait locus (QTL) maps for NR. We generated F1 animals by intercrossing (129S6×CBACa) and (MOLF×CBACa). In each intercross, NR was recessive. N2 animals were produced by backcrossing F1s to their respective parental strain. The 232 N2-129S6 and 225 N2-MOLF progenies were evaluated for NR using auditory brainstem response. In 129S6, five QTL were identified on chromosomes (Chr) 17, 18, 14, 11, and 4, referred to as loci nr1, nr2, nr3, nr4, and nr5, respectively. In MOLF, four QTL were found on Chr 4, 17, 6, and 12, referred to as nr7, nr8, nr9, and nr10, respectively. Given that NR QTL were discovered on Chr 4 and 17 in both the N2-129S6 and N2-MOLF cross, we generated two consomic strains by separately transferring 129S6-derived Chr 4 and 17 into an otherwise CBACa background and a double-consomic strain by crossing the two strains. Phenotypic analysis of the consomic strains indicated that whole 129S6 Chr 4 contributes strongly to mid-frequency NR, while whole 129S6 Chr 17 contributes markedly to high-frequency NR. Therefore, we anticipated that the double-consomic strain containing Chr 4 and 17 would demonstrate NR across the mid-and high-frequency range. However, whole 129S6 Chr 17 masks the expression of mid-frequency NR from whole 129S6 Chr 4. To further dissect NR on 129S6 Chr 4 and 17, CBACa.129S6 congenic strains were generated for each chromosome. Phenotypic analysis of the Chr 17 CBACa.129S6 congenic strains further defined the NR region on proximal Chr 17, uncovered another NR locus (nr6) on distal Chr 17, and revealed an epistatic interaction between proximal and distal 129S6 Chr 17.

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“…The expression of fascin-2 is limited to the inner ear and retina (1). The loss of function mutations of fascin-2 have been correlated with hearing loss and autosomal dominant retinitis pigmentosa, presumably because of defective actin bundle structures in hair cell stereocillia and photoreceptors (5)(6)(7)(8)(9)(10). Understanding the molecular mechanisms underlying fascin bundling activity and its regulation may provide new avenues to prevent cancer metastasis and to treat patients with hearing and vision loss.…”

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confidence: 99%

“…Most of the critical fascin residues are positively charged arginine and lysine residues (11). These residues predominantly cluster at two sites, suggesting that these are the two major actin binding sites (ABS1 and ABS2) 5 that cross-link actin filaments through electrostatic interactions. It has been reported that the phosphorylation of Ser 39 by PKC abrogated fascin bundling activity (15).…”

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confidence: 99%

Monoubiquitination Inhibits the Actin Bundling Activity of Fascin

Lin¹,

Lü²,

Mulaj³

et al. 2016

Journal of Biological Chemistry

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Edited by Velia M. FowlerFascin is an actin bundling protein that cross-links individual actin filaments into straight, compact, and stiff bundles, which are crucial for the formation of filopodia, stereocillia, and other finger-like membrane protrusions. The dysregulation of fascin has been implicated in cancer metastasis, hearing loss, and blindness. Here we identified monoubiquitination as a novel mechanism that regulates fascin bundling activity and dynamics. The monoubiquitination sites were identified to be Lys 247 and Lys 250 , two residues located in a positive charge patch at the actin binding site 2 of fascin. Using a chemical ubiquitination method, we synthesized chemically monoubiquitinated fascin and determined the effects of monoubiquitination on fascin bundling activity and dynamics. Our data demonstrated that monoubiquitination decreased the fascin bundling EC 50 , delayed the initiation of bundle assembly, and accelerated the disassembly of existing bundles. By analyzing the electrostatic properties on the solvent-accessible surface of fascin, we proposed that monoubiquitination introduced steric hindrance to interfere with the interaction between actin filaments and the positively charged patch at actin binding site 2. We also identified Smurf1 as a E3 ligase regulating the monoubiquitination of fascin. Our findings revealed a previously unidentified regulatory mechanism for fascin, which will have important implications for the understanding of actin bundle regulation under physiological and pathological conditions.The compact and straight actin bundles are critical for mammalian cells to generate finger-like protrusions such as filopodia and stereocillia. These protrusions are required for diverse physiological functions including cell motility, hearing, and nutrient absorption. Fascin is a monomeric actin bundling protein essential for maximal cross-linking of actin filaments into compact and rigid bundles (1). There are three fascin isoforms (fascin-1, -2, and -3) in metazoans, with fascin-1 expressed mostly in cells with neuronal and mesenchymal lineage, fascin-2 expressed in hair cells and photoreceptor cells, and fascin-3 expressed almost exclusively in the testis (1). The dysregulation of fascin proteins has been associated with various diseases. For example, fascin-1 (hereafter referred to as fascin) is overexpressed in almost all the carcinomas (2, 3). It is believed that fascin promotes cancer metastasis by facilitating the formation of filopodia and invadopodia, which promote cancer cell motility and invasiveness (2, 4). The expression of fascin-2 is limited to the inner ear and retina (1). The loss of function mutations of fascin-2 have been correlated with hearing loss and autosomal dominant retinitis pigmentosa, presumably because of defective actin bundle structures in hair cell stereocillia and photoreceptors (5-10). Understanding the molecular mechanisms underlying fascin bundling activity and its regulation may provide new avenues to prevent cancer metastasis and to treat pat...

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The R109H Variant of Fascin-2, a Developmentally Regulated Actin Crosslinker in Hair-Cell Stereocilia, Underlies Early-Onset Hearing Loss of DBA/2J Mice

Cited by 112 publications

References 44 publications

Molecular Mechanism of Fascin Function in Filopodial Formation

Molecular Mechanism of Fascin Function in Filopodial Formation

Resistance to Noise-Induced Hearing Loss in 129S6 and MOLF Mice: Identification of Independent, Overlapping, and Interacting Chromosomal Regions

Monoubiquitination Inhibits the Actin Bundling Activity of Fascin

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