Document Detail

Mammalian prestin is a weak Cl⁻/HCO₃⁻ electrogenic antiporter.
MedLine Citation:
PMID:  22890707     Owner:  NLM     Status:  MEDLINE    
The lateral membrane of mammalian cochlear outer hair cells contains prestin, a protein which can act as a fast voltage-driven actuator responsible for electromotility and enhanced sensitivity to sound. The protein belongs to the SLC26 family of transporters whose members are characterised as able to exchange halides for SO(4)(2-) or HCO(3)(-) yet previous analyses of mammalian prestin have suggested that such exchange functions were minimal. Here anion transport is investigated both in guinea-pig outer hair cells (OHCs) and in an expression system where we employ a sensitive intracellular pH (pH(i)) probe, pHluorin, to report HCO(3)(-) transport and to monitor the small pH(i) changes observable in the cells. In the presence of extracellular HCO(3)(-), pH(i) recovered from an acid load 4 times faster in prestin-transfected cells. The acceleration required a chloride gradient established by reducing extracellular chloride to 2 mm. Similar results were also shown using BCECF as an alternative pH(i) sensor, but with recovery only found in those cells expressing prestin. Simultaneous electrophysiological recording of the transfected cells during bicarbonate exposure produced a shift in the reversal potential to more negative potentials, consistent with electrogenic transport. These data therefore suggest that prestin can act as a weak Cl(-)/HCO(3)(-) antiporter and it is proposed that, in addition to participating in wide band cochlear sound amplification, prestin may also be involved in the slow time scale (>10 s) phenomena where changes in cell stiffness and internal pressure have been implicated. The results show the importance of considering the effects of the endogenous bicarbonate buffering system in evaluating the function of prestin in cochlear outer hair cells.
P Mistrík; N Daudet; K Morandell; J F Ashmore
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2012-08-13
Journal Detail:
Title:  The Journal of physiology     Volume:  590     ISSN:  1469-7793     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2012 Nov 
Date Detail:
Created Date:  2012-11-16     Completed Date:  2013-05-01     Revised Date:  2013-12-05    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  5597-610     Citation Subset:  IM    
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MeSH Terms
Action Potentials
Anion Transport Proteins / genetics,  physiology*
Bicarbonates / metabolism
CHO Cells
Chloride-Bicarbonate Antiporters / physiology*
Chlorine / metabolism
Green Fluorescent Proteins / genetics,  metabolism
Guinea Pigs
Hair Cells, Auditory, Outer / physiology
Hydrogen-Ion Concentration
Recombinant Fusion Proteins / genetics,  metabolism
Reg. No./Substance:
0/Anion Transport Proteins; 0/Bicarbonates; 0/Chloride-Bicarbonate Antiporters; 0/PHluorin; 0/Pres protein, rat; 0/Recombinant Fusion Proteins; 147336-22-9/Green Fluorescent Proteins; 4R7X1O2820/Chlorine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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