Dominant-negative inhibition of M-like potassium conductances in hair cells of the mouse inner ear.
Sensory hair cells of the inner ear express multiple physiologically defined conductances, including mechanotransduction, Ca(2+), Na(+), and several distinct K(+) conductances, all of which are critical for normal hearing and balance function. Yet, the molecular underpinnings and their specific contributions to sensory signaling in the inner ear remain obscure. We sought to identify hair-cell conductances mediated by KCNQ4, which, when mutated, causes the dominant progressive hearing loss DFNA2. We used the dominant-negative pore mutation G285S and packaged the coding sequence of KCNQ4 into adenoviral vectors. We transfected auditory and vestibular hair cells of organotypic cultures generated from the postnatal mouse inner ear. Cochlear outer hair cells and vestibular type I cells that expressed the transfection marker, green fluorescent protein, and the dominant-negative KCNQ4 construct lacked the M-like conductances that typify nontransfected control hair cells. As such, we conclude that the M-like conductances in mouse auditory and vestibular hair cells can include KCNQ4 subunits and may also include KCNQ4 coassembly partners. To examine the function of M-like conductances in hair cells, we recorded from cells transfected with mutant KCNQ4 and injected transduction current waveforms in current-clamp mode. Because the M-like conductances were active at rest, they contributed to the very low potassium-selective input resistance, which in turn hyperpolarized the resting potential and significantly attenuated the amplitude of the receptor potential. Modulation of M-like conductances may allow hair cells the ability to control the amplitude of their response to sensory stimuli.
Holt
Jeffrey R
JR
Department of Neuroscience, University of Virginia, Charlottesville, Virginia 22908, USA. jeffholt@virginia.edu
Stauffer
Eric A
EA
Abraham
David
D
Géléoc
Gwenaëlle S G
GS
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D007758:Ear, Inner / Q000166:cytology*; D004558:Electric Stimulation / Q000379:methods; D004622:Embryo, Mammalian; D015870:Gene Expression / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D005822:Genetic Vectors / Q000502:physiology; D005998:Glycine / Q000235:genetics; D006199:Hair Cells, Auditory, Inner / Q000502:physiology*; D006801:Humans; D051656:KCNQ Potassium Channels / Q000235:genetics / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology / Q000528:radiation effects; D051379:Mice; D009154:Mutation / Q000502:physiology; D009433:Neural Inhibition / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D009924:Organ Culture Techniques; D018408:Patch-Clamp Techniques / Q000379:methods; D012444:Saccule and Utricle / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D012694:Serine / Q000235:genetics; D014162:Transfection / Q000379:methods
D051656:KCNQ Potassium Channels; C492167:Kcnq4 protein, mouse; D012694:Serine; D005998:Glycine
J Physiol. 1999 Nov 1;520 Pt 3:653-60
10545133
Proc Natl Acad Sci U S A. 2000 Apr 11;97(8):3786-8
10760249
Proc Natl Acad Sci U S A. 2000 Apr 11;97(8):4333-8
10760300
J Neurophysiol. 2000 Jul;84(1):139-51
10899192
J Gene Med. 2000 Jul-Aug;2(4):250-9
10953916
Brain Res Mol Brain Res. 2000 Oct 20;82(1-2):137-49
11042367
Am J Physiol Cell Physiol. 2001 Mar;280(3):C473-80
11171566
Am J Physiol Cell Physiol. 2001 Apr;280(4):C859-66
11245603
Neuropharmacology. 2001 Jun;40(7):888-98
11378159
Gene Ther. 2001 May;8(10):789-94
11420643
Brain Res Brain Res Protoc. 2002 Feb;9(1):65-76
11852272
Ann Otol Rhinol Laryngol. 2002 Mar;111(3 Pt 1):267-74
11915881
Audiol Neurootol. 2002 Jan-Feb;7(1):9-12
11914518
Audiol Neurootol. 2002 Jan-Feb;7(1):40-4
11914525
Audiol Neurootol. 2002 May-Jun;7(3):157-60
12053137
J Neurosci. 2003 Mar 15;23(6):2141-9
12657673
Nat Neurosci. 2003 Oct;6(10):1019-20
12973354
J Biol Chem. 2004 Jan 9;279(2):1233-41
14585842
Biochim Biophys Acta. 2004 Jan 28;1660(1-2):1-6
14757214
J Assoc Res Otolaryngol. 2004 Jun;5(2):215-26
15357422
J Assoc Res Otolaryngol. 2004 Sep;5(3):270-84
15492886
Nature. 1980 Feb 14;283(5748):673-6
6965523
J Physiol. 1992 Mar;448:73-98
1593487
J Neurophysiol. 1996 Aug;76(2):995-1004
8871214
J Neurosci. 1997 Nov 15;17(22):8739-48
9348343
J Virol. 1998 Feb;72(2):926-33
9444984
Proc Natl Acad Sci U S A. 1998 Mar 3;95(5):2509-14
9482916
J Neurosci. 1998 Sep 15;18(18):7487-501
9736667
Pflugers Arch. 1999 Feb;437(3):409-16
9914397
Cell. 1999 Feb 5;96(3):437-46
10025409
J Neurosci. 1999 Mar 1;19(5):1691-7
10024355
Neuron. 1999 Feb;22(2):217-9
10069328
J Neurophysiol. 1999 Apr;81(4):1881-8
10200223
J Neurosci. 2004 Dec 8;24(49):11148-59
15590931
Nature. 2004 Dec 9;432(7018):723-30
15483558
J Neurophysiol. 2005 Jan;93(1):251-66
15240767
Pflugers Arch. 2005 Apr;450(1):34-44
15660259
J Neurosci. 2005 Oct 5;25(40):9285-93
16207888
EMBO J. 2006 Feb 8;25(3):642-52
16437162
J Neurosci. 2006 Oct 4;26(40):10253-69
17021181
Brain Res. 2007 Mar 30;1139:117-25
17292869