How do the senses of touch, pain and hearing work from a biochemical perspective? Macroscopic distortions of tissues change molecular shapes of proteins in sensory nerve endings, which leads to transmission of signals to the brain. However, all cell-types are known to sense their distortion, from the most primitive archaea to mammalian cells? The erythrocyte (red blood cell; RBC) is no exception; it has been the subject of our latest work in this area.
Imagine distorting these microscopic “bags of enzymes” and observing that the rates of reactions inside them increase dramatically; and the transport of ions across their membranes is also substantially enhanced! This is exactly what we recently discovered while monitoring chemical reactions in RBCs by using NMR spectroscopy. Novel molecular and spectroscopic tools to address this field, and novel explanations for shape and volume control by RBCs, have emerged from this work.
Distortion of RBCs was achieved in a variably-stretchable-gel apparatus [1-3] while metabolism was followed with 13C-labelled glucose that was converted to 13C-labelled lactate. Concurrently, the cation transport was measured using 133Cs+, a quadrupolar nucleus that gives separate NMR signals from inside and outside RBCs [4]. This makes measuring membrane transport facile. We will present the NMR-based evidence for RBC distortion, and the methods used for the metabolic and membrane-transport analyses.
Our working hypothesis on the mechanism of the cell-shape-induced metabolic and membrane-transport responses will be presented, along with an outline of future directions for this project.