The Use of Micropipette Aspiration to Measure Cortex Tension in HeLa Cells and Cardiac Myocytes

Abstract

A cell’s biophysical properties control changes in its shape that drive important biological processes, such as cell division, development, and migration. Changes in the mechanical properties of cells and tissues can also indicate pathophysiological states in the body. Shape changes are controlled by changes in tension of the cellular cortex, which is a thin actin network beneath the plasma membrane. By investigating this biophysical property of cortex tension, we are able to gain greater insight into the many biological processes it is involved in. Non-muscle myosin II (MII) is the motor protein that generates the forces driving this cortex tension. There are two NMII paralogs with distinct biophysical properties, and our research in HeLa cells has revealed NMIIA to be the paralog responsible for generating cortex tension. Here we show, for the first time that this technique can be applied to cardiomyocytes as well to elucidate the relationship between cortex tension and the contraction and relaxation of the beating cycle of these cells.