Role of the Rhamnosyl Residue of Ouabain in the Activation of the Na,K-ATPase Signaling Function

• Published in: Life (Basel, Switzerland) Vol. 13; no. 7; p. 1500
• Main Authors: Rogachevskii, Ilya V, Samosvat, Dmitriy M, Penniyaynen, Valentina A, Plakhova, Vera B, Podzorova, Svetlana A, Ma, Ke, Zegrya, Georgy G, Krylov, Boris V
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01-07-2023; MDPI
• Subjects: Adenosine triphosphatase; Amino acids; Analgesics; Binding; Calcium ions; Calcium signalling; Care and treatment; Cell culture; Chemical properties; Chronic pain; Development and progression; Health aspects; Hydrogen bonding; Hydrogen bonds; Hydrophobicity; Ionic interactions; Ions; Ligands; Low concentrations; Modelling; Na+/K+-exchanging ATPase; Na,K-ATPase; Narcotics; NaV1.8 channel; Neurons; Opioid receptors; ouabagenin; Ouabain; Pain; Pain perception; patch-clamp method; Pharmaceutical research; Physiological aspects; Physiological effects; Physiology; Receptors; Residues; rhamnosyl residue; Sodium channels (voltage-gated); Steroids; Structural members; Russia; ouabain; patch-clamp method; docking; NaV1.8 channel; Na,K-ATPase; rhamnosyl residue; nociception; analgesics; organotypic tissue culture method; ouabagenin
• ISSN: 2075-1729; 2075-1729
• DOI: 10.3390/life13071500

The signaling or non-pumping Na,K-ATPase function was first observed by us in the nociceptive neuron; Na,K-ATPase transduced the signals from the opioid-like receptors to Na
1.8 channels. This study elucidates the role of the rhamnosyl residue of ouabain in the activation of the Na,K-ATPase signaling function. The effects resulting from activation of Na,K-ATPase signaling by the Ca
chelate complex of ouabain (EO) are not manifested upon removal of the rhamnosyl residue, as demonstrated in viable cells by the highly sensitive patch-clamp and organotypic cell culture methods. Docking calculations show that the rhamnosyl residue is involved in five intermolecular hydrogen bonds with the Na,K-ATPase α1-subunit, which are fundamentally important for activation of the Na,K-ATPase signaling function upon EO binding. The main contribution to the energy of EO binding is provided by its steroid core, which forms a number of hydrogen bonds and hydrophobic interactions with Na,K-ATPase that stabilize the ligand-receptor complex. Another critically important role in EO binding is expected to be played by the chelated Ca
cation, which should switch on strong intermolecular ionic interactions between the EO molecule and two α1-Na,K-ATPase amino acid residues, Glu116 and Glu117.