Loss, Restoration, and Maintenance of Plasma Membrane Integrity

A break in the integrity of the plasma membrane immediately compromises this structure’s essential role as a barrier, and this can kill the affected cell. Yet animal cell plasma membranes, unprotected by a cell wall, are highly vulnerable to mechanically induced disruption. Moreover, many tissue environments generate and receive “physiological” levels of mechanical force that impose shear, tensile, and compressive stresses on constituent cells. We examine here the tissue conditions that lead to membrane disruptions and the mechanisms that cells use for preventing disruption-induced death and for rapidly restoring membrane integrity. Mechanical stress also induces an adaptive response by cells, which must sense and respond to this stimulus. A skeletal muscle, for example, experiences during its lifetime a highly variable degree of mechanical load. Its individual myofibers must adapt to this changing mechanical environment, hypertrophying in response to increased load and atrophying in response to decreased load. Such changes in tissue architecture are important because they improve mechanical functioning, make economical use of valuable resources, repair or replace injured components, and/or prevent future injury. We here review briefly what is known about the role of plasma membrane disruption in transducing cell responses to mechanical load.