Hypothesized diprotomeric enzyme complex supported by stochastic modelling of palytoxin-induced Na/K pump channels.

Gabriel D Vilallonga,Antônio-Carlos G De Almeida,Sergio V A Campos,Antônio M Rodrigues,Kelison T Ribeiro

doi:10.1098/rsos.172155

Abstract

The sodium–potassium pump (Na+/K+ pump) is crucial for cell physiology. Despite great advances in the understanding of this ionic pumping system, its mechanism is not completely understood. We propose the use of a statistical model checker to investigate palytoxin (PTX)-induced Na+/K+ pump channels. We modelled a system of reactions representing transitions between the conformational substates of the channel with parameters, concentrations of the substates and reaction rates extracted from simulations reported in the literature, based on electrophysiological recordings in a whole-cell configuration. The model was implemented using the UPPAAL-SMC platform. Comparing simulations and probabilistic queries from stochastic system semantics with experimental data, it was possible to propose additional reactions to reproduce the single-channel dynamic. The probabilistic analyses and simulations suggest that the PTX-induced Na+/K+ pump channel functions as a diprotomeric complex in which protein–protein interactions increase the affinity of the Na+/K+ pump for PTX.

Highlights

The mechanism for moving sodium and potassium ions through the cell membrane
Both against their concentration gradients) is an active transport process involving the hydrolysis of adenosine triphosphate (ATP)
This pumping system is crucial for cell physiology, in neurons [1]

Summary

Introduction

The mechanism for moving sodium and potassium ions through the cell membrane Both against their concentration gradients) is an active transport process involving the hydrolysis of adenosine triphosphate (ATP). This mechanism uses an enzyme called Na+/K+-ATPase that accomplishes the transport of three Na+ molecules and two K+. This pumping system is crucial for cell physiology, in neurons [1]. The Albers–Post model is the most acceptable model for explaining how Na+/K+-

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