A Molecular Mechanism for Electrical Tuning of Cochlear Hair Cells

Ramanathan, Krishnan; Michael, Timothy H.; Jiang, Guo Jian; Hiel, Hakim; Fuchs, Paul

doi:10.1126/science.283.5399.215

Cited by 173 publications

(182 citation statements)

References 21 publications

Supporting

Mentioning

169

Contrasting

Unclassified

Order By: Relevance

“…There is precedent for this observation, as previous work has shown dissociation between mRNA expression and protein levels (Gygi et al 1999;Ghaemmaghami et al 2003). We have since established that Slo delivery to the surface of the cell is inhibited by beta-1 and beta-4 subunits (Bai et al 2010, under review), which are expressed at higher levels in LF hair cells (Ramanathan et al 1999(Ramanathan et al , 2000Bai et al 2010, under review).…”

Section: Tablementioning

confidence: 96%

Gene Expression Gradients along the Tonotopic Axis of the Chicken Auditory Epithelium

Frucht

Uduman

Kleinstein

et al. 2011

JARO

View full text Add to dashboard Cite

There are known differences in the properties of hair cells along the tonotopic axis of the avian auditory epithelium, the basilar papilla (BP). To determine the genetic basis of these differences, we compared gene expression between the high-(HF), middle-, and lowfrequency (LF) thirds of 0-day-old chick auditory epithelia. RNA amplified from each sample was hybridized to whole-genome chicken arrays and GeneSpring software was used to identify differentially expressed genes. Two thousand six hundred sixty-three genes were found to be differentially expressed between the HF and LF segments, using a fold-change cutoff of 2 and a p value of 0.05. Many ion channel genes were differentially expressed between the HF and LF regions of the BP, an expression pattern that was previously established for some but not all of these genes. Quantitative PCR was used to verify tonotopic expression of 15 genes, including KCNMA1 (Slo) and its alternatively spliced STREX exon. Gene set enrichment analyses (GSEA) were performed on the microarray data and revealed many microRNA gene sets significantly enriched in the HF relative to the LF end, suggesting a tonotopic activity gradient. GSEA also suggested differential activity of the kinases protein kinase C and protein kinase A at the HF and LF ends, an interesting corollary to the observation that there is tonotopic expression of the STREX exon that confers on Slo sensitivity to the activity of kinases. Taken together, these results suggest mechanisms of induction and maintenance of tonotopicity and enhance our understanding of the complex nature of proximal-distal gene expression gradients in the chicken BP.

show abstract

Section: Tablementioning

confidence: 96%

Gene Expression Gradients along the Tonotopic Axis of the Chicken Auditory Epithelium

Frucht

Uduman

Kleinstein

et al. 2011

JARO

View full text Add to dashboard Cite

show abstract

“…First, the stoichiometry of the assembly of ␤-and ␣-subunits may influence the gating range of native BK channels. Second, there is evidence that the ability of ␤-subunits to influence the gating range depends on the identity of the ␣-subunit splice variant (Ramanathan et al, 1999). Either or both of these factors may contribute to differences in the gating range between native BK channels in chromaffin cells and channels arising from the coexpression of ␤3 and ␣-subunits.…”

Section: Discussionmentioning

confidence: 99%

“…The ␤3 subunit shifts gating of Slo subunits A major functional role of the previously described ␤1 and ␤2 subunits is to produce a shift in activation by Ca 2ϩ to more negative membrane potentials (McManus et al, 1995;Dworetzky et al, 1996;Wallner et al, 1996;Saito et al, 1997;Ramanathan et al, 1999). Thus, smooth muscle BK channels or other BK channels containing a ␤1 subunit can be activated by elevations of submembrane Ca 2ϩ even at membrane potentials near rest.…”

Section: Inactivation Properties Of Slo␤3 Channels Share Key Similarimentioning

confidence: 99%

“…BK channels are formed from four ␣-subunits (Shen et al, 1994) arising from the Slo gene product (Atkinson et al, 1991;Adelman et al, 1992;Butler et al, 1993). In addition, in some tissues, including smooth muscle (Knaus et al, 1994a,b) and cochlea (Ramanathan et al, 1999), an accessory ␤-subunit can regulate BK channel gating profoundly. ␤-Subunits appear to be responsible for the increased sensitivity of smooth muscle BK channels to C a 2ϩ (McManus et al, 1995) and may play a role in the frequency tuning of hair cells (Ramanathan et al, 1999).…”

mentioning

confidence: 99%

“…In addition, in some tissues, including smooth muscle (Knaus et al, 1994a,b) and cochlea (Ramanathan et al, 1999), an accessory ␤-subunit can regulate BK channel gating profoundly. ␤-Subunits appear to be responsible for the increased sensitivity of smooth muscle BK channels to C a 2ϩ (McManus et al, 1995) and may play a role in the frequency tuning of hair cells (Ramanathan et al, 1999). Although ␤-subunits may account for some of the diversity of BK channels, the BK phenotype in many cells remains unexplained (McManus, 1991).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Molecular Basis for the Inactivation of Ca²⁺- and Voltage-Dependent BK Channels in Adrenal Chromaffin Cells and Rat Insulinoma Tumor Cells

Xia¹,

Ding²,

1999

View full text Add to dashboard Cite

Large-conductance Ca 2ϩ -and voltage-dependent potassium (BK) channels exhibit functional diversity not explained by known splice variants of the single Slo ␣-subunit. Here we describe an accessory subunit (␤3) with homology to other ␤-subunits of BK channels that confers inactivation when it is coexpressed with Slo. Message encoding the ␤3 subunit is found in rat insulinoma tumor (RINm5f) cells and adrenal chromaffin cells, both of which express inactivating BK channels. Channels resulting from coexpression of Slo ␣ and ␤3 subunits exhibit properties characteristic of native inactivating BK channels. Inactivation involves multiple cytosolic, trypsin-sensitive domains. The time constant of inactivation reaches a limiting value ϳ25-30 msec at Ca 2ϩ of 10 M and positive activation potentials. Unlike Shaker N-terminal inactivation, but like native inactivating BK channels, a cytosolic channel blocker does not compete with the native inactivation process. Finally, the ␤3 subunit confers a reduced sensitivity to charybdotoxin, as seen with native inactivating BK channels. Inactivation arises from the N terminal of the ␤3 subunit. Removal of the ␤3 N terminal (33 amino acids) abolishes inactivation, whereas the addition of the ␤3 N terminal onto the ␤1 subunit confers inactivation. The ␤3 subunit shares with the ␤1 subunit an ability to shift the range of voltages over which channels are activated at a given Ca 2ϩ . Thus, the ␤-subunit family of BK channels regulates a number of critical aspects of BK channel phenotype, including inactivation and apparent Ca 2ϩ sensitivity.

show abstract

Global cDNA Amplification Combined with Real-Time RT–PCR: Accurate Quantification of Multiple Human Potassium Channel Genes at the Single Cell Level

Al-Taher

Bashein

Nolan

et al. 2000

Yeast

View full text Add to dashboard Cite

We have developed a sensitive quantitative RT–PCR procedure suitable for the analysis of small samples, including single cells, and have used it to measure levels of potassium channel mRNAs in a panel of human tissues and small numbers of cells grown in culture. The method involves an initial global amplification of cDNA derived from all added polyadenylated mRNA followed by quantitative RT–PCR of individual genes using specific primers. In order to facilitate rapid and accurate processing of samples, we have adapted the approach to allow use ofTaqMan™real-time quantitative PCR. We demonstrate that the approach represents a major improvement over existing conventional and real-time quantitative PCR approaches, since it can be applied to samples equivalent to a single cell, is able to accurately measure expression levels equivalent to less than 1/100th copy/cell (one specific cDNA molecule present amongst108total cDNA molecules). Furthermore, since the initial step involves a global amplification of all expressed genes, a permanent cDNA archive is generated from each sample, which can be regenerated indefinitely for further expression analysis.

show abstract

A Molecular Mechanism for Electrical Tuning of Cochlear Hair Cells

Cited by 173 publications

References 21 publications

Gene Expression Gradients along the Tonotopic Axis of the Chicken Auditory Epithelium

Gene Expression Gradients along the Tonotopic Axis of the Chicken Auditory Epithelium

Molecular Basis for the Inactivation of Ca²⁺- and Voltage-Dependent BK Channels in Adrenal Chromaffin Cells and Rat Insulinoma Tumor Cells

Global cDNA Amplification Combined with Real-Time RT–PCR: Accurate Quantification of Multiple Human Potassium Channel Genes at the Single Cell Level

Contact Info

Product

Resources

About

A Molecular Mechanism for Electrical Tuning of Cochlear Hair Cells

Cited by 173 publications

References 21 publications

Gene Expression Gradients along the Tonotopic Axis of the Chicken Auditory Epithelium

Gene Expression Gradients along the Tonotopic Axis of the Chicken Auditory Epithelium

Molecular Basis for the Inactivation of Ca2+- and Voltage-Dependent BK Channels in Adrenal Chromaffin Cells and Rat Insulinoma Tumor Cells

Global cDNA Amplification Combined with Real-Time RT–PCR: Accurate Quantification of Multiple Human Potassium Channel Genes at the Single Cell Level

Contact Info

Product

Resources

About

Molecular Basis for the Inactivation of Ca²⁺- and Voltage-Dependent BK Channels in Adrenal Chromaffin Cells and Rat Insulinoma Tumor Cells