Forisomes: Mechano-Proteins that Exert Force in Contraction and Expansion

Forisomes are elongate protein bodies of up to 30 gm length from cells of the sieve tube network of higher plants. In this natural microfluidics system, they act as reversible stopcocks by undergoing rapid conformational changes which involve more than three-fold increases in volume. The conformational switch is controlled by Ca2+ with a threshold concentration in the nM range. We here report recent progress in our attempts to define the technological potential of this novel biological actuator.