Motor protein function

Cilia are composed of cytoskeletal filaments and molecular motors and are characterized by a wave-like motion. Here the authors show that this motion is reconstituted in vitro from the self-assembly of polymerizing actin filaments and myosin motors.

Release of the ATP hydrolysis product orthophosphate (Pi) from the myosin active site is central in force generation but is poorly understood. Here, Moretto et al. present evidence for multistep Pi-release reconciling apparently contradictory results.

It is unclear how bacterial cells adapt the reversible switching of flagellar motor rotation to environments of different viscosities. Here, Antani et al. show that flagellar mechanosensors allosterically control the motor’s binding affinity for the chemotaxis response regulator, CheY-P, to adapt flagellar switching over varying viscous loads.

Plasmodium falciparum moves by an atypical process called gliding motility which comprises of atypical myosin A (PfMyoA) and filaments of the dynamic and divergent PfActin-1 (PfAct1). Here authors present the cryo-EM structure of PfMyoA bound to filamentous PfAct1 stabilized with jasplakinolide and provide insights into the interactions that are required for the parasite to produce the force and motion required for infectivity.

Minamino et al. report that the bacterial FlgN chaperone acts as a switch to activate a backup mechanism for H⁺-coupled flagellar protein export by interacting with FlhA_C to activate the Na⁺-driven export engine. The proposed mechanism helps to explain how bacteria can maintain flagellar protein export when the ATPase complex export machinery becomes non-functional.