title: Covalent binding of cisplatin impairs the function of Na(+)/K(+)-ATPase by binding to its cytoplasmic part.
abstract: This study was aimed at verifying the hypothesis that acute kidney failure accompanying cisplatin administration in the cancer therapy could be due to cisplatin interaction with the cytoplasmic part of Na(+)/K(+)-ATPase. Our results demonstrated that cisplatin-binding caused inhibition of Na(+)/K(+)-ATPase, in contrast to other platinated chemotherapeutics such as carboplatin and oxaliplatin, which are known to be much less nephrotoxic. To acquire more detailed structural information, we performed a series of experiments with the isolated large cytoplasmic segment connecting transmembrane helices 4 and 5 (C45 loop) of Na(+)/K(+)-ATPase. Electrochemistry showed that cisplatin is bound to the cysteine residues of the C45 loop, mass spectrometry revealed a modification of the C45 peptide fragment GSHMASLEAVETLGSTSTICSDK, which contains the conserved phosphorylated residue Asp369. Hence, we hypothesize that binding of cisplatin to Cys367 can cause sterical obstruction during the phosphorylation or dephosphorylation step of the Na(+)/K(+)-ATPase catalytic cycle.
authors.affiliation: Department of Biophysics, Palacký University in Olomouc, Olomouc, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Huličiak
authors.forename: Jan
authors.initials: J
authors.lastname: Vacek
authors.forename: Marek
authors.initials: M
authors.lastname: Sebela
authors.forename: Eva
authors.initials: E
authors.lastname: Orolinová
authors.forename: Joanna
authors.initials: J
authors.lastname: Znaleziona
authors.forename: Marika
authors.initials: M
authors.lastname: Havlíková
authors.forename: Martin
authors.initials: M
authors.lastname: Kubala
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000378:metabolism* / Q000494:pharmacology; D002540:Cerebral Cortex / Q000201:enzymology; D002945:Cisplatin / Q000378:metabolism* / Q000494:pharmacology; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013552:Swine
chemical_list: D000970:Antineoplastic Agents; D000254:Sodium-Potassium-Exchanging ATPase; D002945:Cisplatin