Cages – a New Plasma Membrane Structure

The Heit lab is excited to announce the discovery of membrane cages, a previously undescribed membrane structure.

This discovery has been published in the journal Scientific Reports. Membrane cages act to transiently block the diffusion of membrane proteins, thus structuring proteins in cellular membranes over short periods of time. This discovery was made, with our collaborator Dr John de Bruyn in the Department of Physics, through a combination of super resolution microscopy and classical cell biology techniques. We used high-speed super resolution microscopy to track the diffusion of CD93 – a macrophage receptor – and discovered that CD93 occasionally became trapped into membrane sub-regions that did not correlate to other known cellular structures. Through a range of experiments we were able to demonstrate that these “cages” were short lived (milliseconds to seconds), were independent of a previously described membrane structures, and that cages require cholesterol for their stability and strength.

Much remains to be discovered about the purpose and composition of this new cellular structure, but we expect cages to play an important role in structuring membrane proteins into functional units. Of particular interest to our lab is the negative impact of excess cholesterol on cages, an observation which suggests that some of the cellular deficiencies observed during diseases such as atherosclerosis (heart disease) may be a product of altered cage structure or function.