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ZFIN ID: ZDB-PUB-151210-4
A K(+)-selective CNG channel orchestrates Ca2(+) signalling in zebrafish sperm
Fechner, S., Alvarez, L., Bönigk, W., Müller, A., Berger, T., Pascal, R., Trötschel, C., Poetsch, A., Stölting, G., Siegfried, K.R., Kremmer, E., Seifert, R., Kaupp, U.B.
Date: 2015
Source: eLIFE 4: (Journal)
Registered Authors: Siegfried, Kellee
Keywords: biophysics, cell biology, structural biology, zebrafish
MeSH Terms:
  • Animals
  • Calcium Signaling*
  • Cyclic Nucleotide-Gated Cation Channels/metabolism*
  • Male
  • Potassium/metabolism*
  • Spermatozoa/drug effects
  • Spermatozoa/physiology*
  • Zebrafish/physiology*
PubMed: 26650356 Full text @ Elife
Calcium in the flagellum controls sperm navigation. In sperm of marine invertebrates and mammals, Ca2(+) 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 Ca2(+) 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 Ca2(+) entry. Ca2(+) 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.