title: Channel induction by palytoxin in yeast cells expressing Na+,K+-ATPase or its chimera with sarco/endoplasmic reticulum Ca2+-ATPase.
abstract: Palytoxin (PTX) induces a cation channel through interaction with Na(+),K(+)-ATPase. It is unclear how this action relates to the enzyme catalytic activity. We examined whether the action of PTX depends on the catalytic domain specific for Na(+),K(+)-ATPase. Wild-type Na(+),K(+)-ATPase alpha-subunit (NNN) or its chimera (NCN), in which the catalytic domain was replaced with that of sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase, was co-expressed with beta-subunit in the yeast Saccharomyces cerevisiae. PTX (0.1-100 nM) increased K(+) efflux in NNN- or NCN-transfected cells to a similar degree but not in non-transfected cells. When ouabain-resistant NNN and NCN were expressed, PTX also increased K(+) efflux. Ouabain inhibited the effect of PTX in NNN or NCN cells but not in ouabain-resistant cells. These data suggest that the channel-forming action of PTX does not depend on the catalytic domain species.
authors.affiliation: Department of Veterinary Pharmacology, Faculty of Agriculture, Miyazaki University, 889-2192, Miyazaki, Japan. itokt@cc.miyazaki-u.ac.jp
authors.forename: Katsuaki
authors.initials: K
authors.lastname: Ito
authors.forename: Isao
authors.initials: I
authors.lastname: Toyoda
authors.forename: Masato
authors.initials: M
authors.lastname: Higashiyama
authors.forename: Daisuke
authors.initials: D
authors.lastname: Uemura
authors.forename: Masa H
authors.initials: MH
authors.lastname: Sato
authors.forename: Shige H
authors.initials: SH
authors.lastname: Yoshimura
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Ishii
authors.forename: Kunio
authors.initials: K
authors.lastname: Takeyasu
mesh_terms: D000178:Acrylamides / Q000494:pharmacology*; D000252:Calcium-Transporting ATPases / Q000737:chemistry / Q000235:genetics; D020134:Catalytic Domain; D003064:Cnidarian Venoms; D004721:Endoplasmic Reticulum / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017136:Ion Transport / Q000187:drug effects; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D000095702:Polyether Toxins
chemical_list: D000178:Acrylamides; D000252:Calcium-Transporting ATPases; D003064:Cnidarian Venoms; D004791:Enzyme Inhibitors; D010042:Ouabain; D011188:Potassium; D011993:Recombinant Fusion Proteins; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; C010272:palytoxin; D000095702:Polyether Toxins