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 α-subunit (NNN) or its chimera (NCN), in which the catalytic domain was replaced with that of sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase, was co-expressed with β-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. [Copyright &y& Elsevier]