Fig. 6: Activation of Hsp26 by phosphorylation-induced unlocking of the MD.

In the inactive state, the MD (dark green) interacts with a big loop of the ACD (orange-red). Therefore, it is buried in the oligomer and not able to bind substrate proteins. The MD can be liberated by increasing temperature, which goes along with the dissociation of the oligomer. Alternatively, phosphorylation in specific parts of the MD, ACD, and CTR (blue) can also lead to the unlocking of the NTR. The circle segments represent the dynamics of the NTR or CTR.