New discovery casts doubt on plasma membrane models

Like planets, the body's cell surfaces look smooth from a distance but hilly closer up. An article published in Communications Biology describes implications, unknown to date, of the way data from cell surfaces are normally interpreted; i.e. as if they lacked topographic features.

When Earth is studied from space, its surface looks smooth, but on zooming in we notice the mountains and valleys. The same applies to cells; without magnification they look smooth, but a closer look reveals both ridges and craters.

Researchers from the Universities of Gothenburg and Uppsala, Sweden, studied how this variation in cell topography affects "diffusion" — how molecules move in the cell membrane. Diffusion is studied to develop models for the membrane's organization and to increase our understanding on the interaction between cell components.

One dimension missing

The basis for the researchers' study was their previous discoveries. These showed that not a single one of 70 cell types studied has a smooth surface.

"Today's dominant models of how the plasma membrane that surrounds the cell is organized are based on two-dimensional interpretation of measurement data. Our study shows that this leads to completely incorrect conclusions, since the cell surface is three-dimensional," says Ingela Parmryd, Senior Lecturer in Cell Biology at Sahlgrenska Academy, University of Gothenburg, the lead author of the article.

In studies of molecular movements, the cell topography can cause both marked underestimation of movement in the membrane and deviant movement patterns. This is shown in the present study, which is groundbreaking in its field.

Fundamental impact

"The goal of our research is to take the great leap forward from current two-dimensional to three-dimensional membrane models. This is going to change the way we perceive fundamental biological processes like cell signaling, cell-to-cell contacts and cell migration — processes that change in pathological states, such as cancer," Ingela Parmryd says.