Sp-tetraKCNG: A novel cyclic nucleotide gated K + channel

• Published in: Biochemical and biophysical research communications Vol. 354; no. 3; pp. 668 - 675
• Main Authors: Galindo, Blanca Estela, de la Vega-Beltrán, José Luis, Labarca, Pedro, Vacquier, Victor D., Darszon, Alberto
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 16.03.2007
• Subjects: Animals; Binding Sites; Cations - metabolism; Cyclic GMP - metabolism; Cyclic nucleotides; Fertilization; Flagellar motility; Ion channels; Lipid Bilayers - metabolism; Male; Molecular Sequence Data; Plasma membrane; Potassium Channels - chemistry; Potassium Channels - metabolism; Potassium Channels, Voltage-Gated - chemistry; Potassium Channels, Voltage-Gated - metabolism; Sequence Analysis, Protein; Sperm; Spermatozoa - chemistry; Spermatozoa - cytology; Spermatozoa - metabolism; Strongylocentrotus purpuratus - physiology; Flagellar motility; Ion channels; Cyclic nucleotides; Fertilization; Sperm; Plasma membrane
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2007.01.035

The sequence of a novel cGMP-regulated, tetrameric, K + selective channel (Sp-tetraKCNG) was discovered in the sea urchin Strongylocentrotus purpuratus. The Sp-tetraKCNG is a single polypeptide made of four KCNG domains similar to voltage-dependent Na + and Ca 2+ channels. Each KCNG domain has six transmembrane segments (S1–S6), the ion pore having the K + selectivity signature GYGD and a cyclic nucleotide-binding domain (CNBD). This novel channel is evolutionary located between K +-selective and voltage-dependent EAG channels and voltage-independent cationic CNG channels. Bilayer reconstitutions demonstrate such a cGMP-regulated K + selective channel in sea urchin spermatozoa.