Protein-protein interactions of a Kvbeta subunit in the cochlea.
Accessory subunits associated with voltage-gated potassium (Kv) channels can influence the biophysical properties and promote the surface expression of channel-forming alpha-subunits. Previously, we cloned several alpha-subunits and a beta-subunit from a cDNA library of the chicken cochlea. In the present study, we raised an antibody against the N-terminus of chicken Kvbeta1.1 (cKvbeta1.1) and characterized the Kvbeta-related polypeptide in cochlear tissues and heterologous cells. The anti-cKvbeta1.1 antibody recognizes a 45-kDa polypeptide in chick cochlear extracts as well as in Chinese hamster ovary (CHO) cells transfected with cKvbeta1.1. The accessory subunit was localized to the ganglion cells of the chick cochlea using immunohistochemistry and in situ hybridization. Coimmunoprecipitation studies show that Kvbeta1.1 interacts with Shaker channel members Kvalpha1.2 and 1.3, both of which colocalize with beta to the cochlear ganglion cells. Additionally, coimmunoprecipitation studies show that Kvalpha1.2 and 1.3 interact with each other, suggesting that these ion channels are formed by heteromultimers. In comparison, Kvbeta did not coprecipitate with a member of the Shal subfamily. The presence of Kvbeta in the cochlea suggests that this subunit contributes to the modulation of auditory signals in the ganglion cells, presumably by regulating properties of inactivation as well as surface expression of Kvalpha channels.
Sokolowski
Bernd
B
Department of Otolaryngology-Head and Neck Surgery, Department of Physiology and Biophysics, University of South Florida College of Medicine, Tampa, Florida 33612, USA. bsokolow@hsc.usf.edu
Harvey
Margaret
M
Venkataramu
Chinnambally
C
Duzhyy
Dmytro
D
D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western / Q000379:methods; D016466:CHO Cells / Q000378:metabolism; D002645:Chickens; D003051:Cochlea / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D007150:Immunohistochemistry / Q000379:methods; D047468:Immunoprecipitation / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D051662:Kv1.1 Potassium Channel; D051663:Kv1.2 Potassium Channel; D010455:Peptides / Q000276:immunology / Q000378:metabolism; D024642:Potassium Channels, Voltage-Gated / Q000145:classification* / Q000276:immunology / Q000378:metabolism*; D011485:Protein Binding; D014162:Transfection / Q000379:methods
D051663:Kv1.2 Potassium Channel; D010455:Peptides; D024642:Potassium Channels, Voltage-Gated; D051662:Kv1.1 Potassium Channel