title: A K(+)-selective CNG channel orchestrates Ca(2+) signalling in zebrafish sperm.
abstract: Calcium in the flagellum controls sperm navigation. In sperm of marine invertebrates and mammals, Ca(2+) signalling has been intensely studied, whereas for fish little is known. In sea urchin sperm, a cyclic nucleotide-gated K(+) channel (CNGK) mediates a cGMP-induced hyperpolarization that evokes Ca(2+) influx. Here, we identify in sperm of the freshwater fish Danio rerio a novel CNGK family member featuring non-canonical properties. It is located in the sperm head rather than the flagellum and is controlled by intracellular pH, but not cyclic nucleotides. Alkalization hyperpolarizes sperm and produces Ca(2+) entry. Ca(2+) induces spinning-like swimming, different from swimming of sperm from other species. The "spinning" mode probably guides sperm into the micropyle, a narrow entrance on the surface of fish eggs. A picture is emerging of sperm channel orthologues that employ different activation mechanisms and serve different functions. The channel inventories probably reflect adaptations to species-specific challenges during fertilization.
authors.affiliation: Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Fechner
authors.affiliation: Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany.
authors.forename: Luis
authors.initials: L
authors.lastname: Alvarez
authors.affiliation: Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Bönigk
authors.affiliation: Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany.
authors.forename: Astrid
authors.initials: A
authors.lastname: Müller
authors.affiliation: Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany.
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Berger
authors.affiliation: Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany.
authors.forename: Rene
authors.initials: R
authors.lastname: Pascal
authors.affiliation: Lehrstuhl Biochemie der Pflanzen, Ruhr-Universität Bochum, Bochum, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Trötschel
authors.affiliation: Lehrstuhl Biochemie der Pflanzen, Ruhr-Universität Bochum, Bochum, Germany.
authors.forename: Ansgar
authors.initials: A
authors.lastname: Poetsch
authors.affiliation: Institute of Complex Systems 4, Forschungszentrum Jülich, Jülich, Germany.
authors.forename: Gabriel
authors.identifier: http://orcid.org/0000-0002-2339-0545
authors.initials: G
authors.lastname: Stölting
authors.affiliation: Biology Department, University of Massachusetts Boston, Boston, United States.
authors.forename: Kellee R
authors.initials: KR
authors.lastname: Siegfried
authors.affiliation: Institut für Molekulare Immunologie, Helmholtz-Zentrum München, München, Germany.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kremmer
authors.affiliation: Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Seifert
authors.affiliation: Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany.
authors.forename: U Benjamin
authors.initials: UB
authors.lastname: Kaupp
mesh_terms: D000818:Animals; D020013:Calcium Signaling; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000378:metabolism*; D008297:Male; D011188:Potassium / Q000378:metabolism*; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology*; D015027:Zebrafish / Q000502:physiology*
chemical_list: D054815:Cyclic Nucleotide-Gated Cation Channels; D011188:Potassium
keywords: biophysics; cell biology; fertilization; potassium channel; sperm signalling; structural biology; zebrafish