Channel induction by palytoxin in yeast cells expressing Na+,K+-ATPase or its chimera with sarco/endoplasmic reticulum Ca2+-ATPase.
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.
Ito
Katsuaki
K
Department of Veterinary Pharmacology, Faculty of Agriculture, Miyazaki University, 889-2192, Miyazaki, Japan. itokt@cc.miyazaki-u.ac.jp
Toyoda
Isao
I
Higashiyama
Masato
M
Uemura
Daisuke
D
Sato
Masa H
MH
Yoshimura
Shige H
SH
Ishii
Toshiaki
T
Takeyasu
Kunio
K
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
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