title: Deciphering the function of the CNGB1b subunit in olfactory CNG channels.
abstract: Olfactory cyclic nucleotide-gated (CNG) ion channels are key players in the signal transduction cascade of olfactory sensory neurons. The second messengers cAMP and cGMP directly activate these channels, generating a depolarizing receptor potential. Olfactory CNG channels are composed of two CNGA2 subunits and two modulatory subunits, CNGA4, and CNGB1b. So far the exact role of the modulatory subunits for channel activation is not fully understood. By measuring ligand binding and channel activation simultaneously, we show that in functional heterotetrameric channels not only the CNGA2 subunits and the CNGA4 subunit but also the CNGB1b subunit binds cyclic nucleotides and, moreover, also alone translates this signal to open the pore. In addition, we show that the CNGB1b subunit is the most sensitive subunit in a heterotetrameric channel to cyclic nucleotides and that it accelerates deactivation to a similar extent as does the CNGA4 subunit. In conclusion, the CNGB1b subunit participates in ligand-gated activation of olfactory CNG channels and, particularly, contributes to rapid termination of odorant signal in an olfactory sensory neuron.
authors.affiliation: Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, D-07743 Jena, Germany.
authors.forename: Vasilica
authors.initials: V
authors.lastname: Nache
authors.affiliation: Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, D-07743 Jena, Germany.
authors.forename: Nisa
authors.initials: N
authors.lastname: Wongsamitkul
authors.affiliation: Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, D-07743 Jena, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Kusch
authors.affiliation: Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, D-07743 Jena, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Zimmer
authors.affiliation: BIOLOG Life Science Institute, Flughafendamm 9A, D-28199 Bremen, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Schwede
authors.affiliation: Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, D-07743 Jena, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Benndorf
mesh_terms: D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000378:metabolism / Q000502:physiology*; D005260:Female; D015640:Ion Channel Gating / Q000502:physiology; D008024:Ligands; D009812:Odorants; D018034:Olfactory Receptor Neurons / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D014982:Xenopus laevis
chemical_list: D054815:Cyclic Nucleotide-Gated Cation Channels; D008024:Ligands; D000242:Cyclic AMP; D006152:Cyclic GMP