Identification of cisplatin-binding sites on the large cytoplasmic loop of the Na⁺/K⁺-ATPase

Abstract

Cisplatin is the most widely used chemotherapeutic drug for the treatment of various types of cancer; however, its administration brings also numerous side effects. It was demonstrated that cisplatin can inhibit the Na⁺/K⁺-ATPase (NKA), which can explain a large part of the adverse effects. In this study, we have identified five cysteinyl residues (C452, C456, C457, C577, and C656) as the cisplatin binding sites on the cytoplasmic loop connecting transmembrane helices 4 and 5 (C45), using site-directed mutagenesis and mass spectrometry experiments. The identified residues are known to be susceptible to glutathionylation indicating their involvement in a common regulatory mechanism.

Keywords:

• Na⁺/K⁺-ATPase
• sodium pump
• C45 loop
• cisplatin
• binding site
• cysteine mutants

Acknowledgements

J. Š. acknowledges Martin Šefl from the Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague for his help with the Matlab data processing. P. Č. would like to acknowledge that the computational resources were provided by the CESNET LM2015042 and the CERIT Scientific Cloud LM2015085, provided under the programme “Projects of Large Research, Development, and Innovations Infrastructures”.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by grant LO1024 from the National Programme of Sustainability I, Ministry of Schools, Youth and Sports, Czech Republic, and by Endowment Fund of Palacky University, Olomouc.