Olga D. Lopina

Learn More
Treatment with ouabain led to massive death of principal cells from collecting ducts (C7-MDCK), indicated by cell swelling, loss of mitochondrial function, an irregular pattern of DNA degradation, and insensitivity to pan-caspase inhibitor. Equimolar substitution of extracellular Na(+) by K(+) or choline(+) sharply attenuated the effect of ouabain on(More)
Na,K-ATPase is highly sensitive to changes in the redox state, and yet the mechanisms of its redox sensitivity remain unclear. We have explored the possible involvement of S-glutathionylation of the catalytic α subunit in redox-induced responses. For the first time, the presence of S-glutathionylated cysteine residues was shown in the α subunit in duck salt(More)
Structural organization of alpha- and beta-subunits of Na+,K+-ATPase in the membrane, the enzyme oligomeric structure, and mechanisms of ATP hydrolysis and cation transport are considered. The data on the structure of cation-binding sites and ion-conductive pathways of the pump are reviewed. The properties of isoforms of both subunits are described. Special(More)
Recently, we reported that ouabain kills renal epithelial and vascular endothelial cells independently of elevation of the [Na(+)](i)/[K(+)](i) ratio. These observations raised the possibility of finding cardiotonic steroids (CTS) that inhibit the Na(+),K(+) pump without attenuating cell survival and vice versa. To test this hypothesis, we compared CTS(More)
The decrease in the oxygen content of tissues, which is observed in a number of pathological processes, inevitably leads to damage. One of the main causes of cell damage and death in hypoxia is the failure of the systems that maintain the ionic balance. Na,K-ATPase is the main ion-transporting protein in the plasma membrane of animal cells, and its(More)
Recent studies demonstrate that cytotoxic actions of ouabain and other cardiotonic steroids (CTS) on renal epithelial cells (REC) are triggered by their interaction with the Na+,K+-ATPase α-subunit but not the result of inhibition of Na+,K+-ATPase-mediated ion fluxes and inversion of the [Na+]i/[K+]i ratio. This study examined the role of mitogen-activated(More)
Highly purified preparations of duck salt gland and canine kidney Na+/K(+)-ATPases with comparable specific activities were used to clarify the causes of previously reported differences between the substrate-velocity curves of these enzymes. When assays were done under identical conditions (pH 7.4; 37 degrees C), and a wide range of closely spaced ATP(More)
On the basis of a review of the literature and a study of the molecular and kinetic properties of Na(+)-K+ ATPase, a model is proposed that explains the regulation of the activity of the enzyme by ATP in terms of an acceleration of the E2----E1 transition. It is presumed that the transition occurs via a short-lived oligomer whose formation is accelerated by(More)
The total Ca-ATPase activity in the sarcoplasmic reticulum (SR) membrane fraction isolated from skeletal muscles of winter hibernating ground squirrel Spermophilus undulatus is ∼2.2-fold lower than in preparations obtained from summer active animals. This is connected in part with ∼10% decrease of the content of Ca-ATPase protein in SR membranes. However,(More)