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Interactions of Cyclic Nucleotide-Gated Channel Subunits and Protein Tyrosine Kinase Probed with Genistein

The cGMP sensitivity of cyclic nucleotide–gated (CNG) channels can be modulated by changes in phosphorylation catalyzed by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases. Previously, we used genistein, a PTK inhibitor, to probe the interaction between PTKs and homomeric channels c...

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Detalles Bibliográficos
Autores principales: Molokanova, Elena, Savchenko, Alexei, Kramer, Richard H.
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 2000
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2232887/
https://www.ncbi.nlm.nih.gov/pubmed/10828243
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author Molokanova, Elena
Savchenko, Alexei
Kramer, Richard H.
author_facet Molokanova, Elena
Savchenko, Alexei
Kramer, Richard H.
author_sort Molokanova, Elena
collection PubMed
description The cGMP sensitivity of cyclic nucleotide–gated (CNG) channels can be modulated by changes in phosphorylation catalyzed by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases. Previously, we used genistein, a PTK inhibitor, to probe the interaction between PTKs and homomeric channels comprised of α subunits (RETα) of rod photoreceptor CNG channels expressed in Xenopus oocytes. We showed that in addition to inhibiting phosphorylation, genistein triggers a noncatalytic interaction between PTKs and homomeric RETα channels that allosterically inhibits channel gating. Here, we show that native CNG channels from rods, cones, and olfactory receptor neurons also exhibit noncatalytic inhibition induced by genistein, suggesting that in each of these sensory cells, CNG channels are part of a regulatory complex that contains PTKs. Native CNG channels are heteromers, containing β as well as α subunits. To determine the contributions of α and β subunits to genistein inhibition, we compared the effect of genistein on native, homomeric (RETα and OLFα), and heteromeric (RETα+β, OLFα+β, and OLFα+RETβ) CNG channels. We found that genistein only inhibits channels that contain either the RETα or the OLFβ subunits. This finding, along with other observations about the maximal effect of genistein and the Hill coefficient of genistein inhibition, suggests that the RETα and OLFβ subunits contain binding sites for the PTK, whereas RETβ and OLFα subunits do not.
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spelling pubmed-22328872008-04-21 Interactions of Cyclic Nucleotide-Gated Channel Subunits and Protein Tyrosine Kinase Probed with Genistein Molokanova, Elena Savchenko, Alexei Kramer, Richard H. J Gen Physiol Original Article The cGMP sensitivity of cyclic nucleotide–gated (CNG) channels can be modulated by changes in phosphorylation catalyzed by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases. Previously, we used genistein, a PTK inhibitor, to probe the interaction between PTKs and homomeric channels comprised of α subunits (RETα) of rod photoreceptor CNG channels expressed in Xenopus oocytes. We showed that in addition to inhibiting phosphorylation, genistein triggers a noncatalytic interaction between PTKs and homomeric RETα channels that allosterically inhibits channel gating. Here, we show that native CNG channels from rods, cones, and olfactory receptor neurons also exhibit noncatalytic inhibition induced by genistein, suggesting that in each of these sensory cells, CNG channels are part of a regulatory complex that contains PTKs. Native CNG channels are heteromers, containing β as well as α subunits. To determine the contributions of α and β subunits to genistein inhibition, we compared the effect of genistein on native, homomeric (RETα and OLFα), and heteromeric (RETα+β, OLFα+β, and OLFα+RETβ) CNG channels. We found that genistein only inhibits channels that contain either the RETα or the OLFβ subunits. This finding, along with other observations about the maximal effect of genistein and the Hill coefficient of genistein inhibition, suggests that the RETα and OLFβ subunits contain binding sites for the PTK, whereas RETβ and OLFα subunits do not. The Rockefeller University Press 2000-06-01 /pmc/articles/PMC2232887/ /pubmed/10828243 Text en © 2000 The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Original Article
Molokanova, Elena
Savchenko, Alexei
Kramer, Richard H.
Interactions of Cyclic Nucleotide-Gated Channel Subunits and Protein Tyrosine Kinase Probed with Genistein
title Interactions of Cyclic Nucleotide-Gated Channel Subunits and Protein Tyrosine Kinase Probed with Genistein
title_full Interactions of Cyclic Nucleotide-Gated Channel Subunits and Protein Tyrosine Kinase Probed with Genistein
title_fullStr Interactions of Cyclic Nucleotide-Gated Channel Subunits and Protein Tyrosine Kinase Probed with Genistein
title_full_unstemmed Interactions of Cyclic Nucleotide-Gated Channel Subunits and Protein Tyrosine Kinase Probed with Genistein
title_short Interactions of Cyclic Nucleotide-Gated Channel Subunits and Protein Tyrosine Kinase Probed with Genistein
title_sort interactions of cyclic nucleotide-gated channel subunits and protein tyrosine kinase probed with genistein
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2232887/
https://www.ncbi.nlm.nih.gov/pubmed/10828243
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