The effect of temperature on the lateral diffusion of plasma membrane proteins.

Cooling is expected to gradually reduce the lateral diffusion of membrane proteins, at a rate predicted from the changes in viscosity and order observed on cooling defined lipids and lipid mixtures. However, a continuous change in diffusion rate with falling temperature is not observed in mammalian cells. Rather, on cooling below around 20 degrees C, protein diffusion rates are found to increase, reaching a new maximum at 15 degrees C. This anomaly in diffusion rate could result in irreversible changes in membrane structure when mammalian cells are cooled to temperatures below 20 degrees C.