Rhomboid distorts lipids to break the viscosity-imposed speed limit of membrane diffusion

How rhomboid proteases act so quickly How enzymes catalyze reactions in the viscous cell membrane is poorly understood. Kreutzberger et al. visualized single molecules of rhomboid intramembrane proteases diffusing in defined nanofabricated membranes and live cells (see the Perspective by Wolfe). They found that the rhomboid protein fold distorts surrounding lipids to reduce local membrane viscosity and enhance enzyme diffusion. The rate of catalysis in cells relies on rapid diffusion, revealing that rhomboid's diffusion has been boosted beyond the normal “speed limit” of the membrane, augmenting the search for substrates. Science , this issue p. eaao0076 ; see also p. 453