Structural Insights into Functional Overlapping and Differentiation among Myosin V Motors

Background: MyoVs are molecular motors widely distributed in eukaryotic cells responsible for membrane trafficking and intracellular transport. Results: The cargo-binding domain from human MyoV paralogs was structurally and biophysically characterized. Conclusion: We identified singular structural changes and molecular events conferring functional differentiation and modulating cargo binding. Significance: This work provides structural insights into cargo recognition and regulatory mechanisms in MyoVs. Myosin V (MyoV) motors have been implicated in the intracellular transport of diverse cargoes including vesicles, organelles, RNA-protein complexes, and regulatory proteins. Here, we have solved the cargo-binding domain (CBD) structures of the three human MyoV paralogs (Va, Vb, and Vc), revealing subtle structural changes that drive functional differentiation and a novel redox mechanism controlling the CBD dimerization process, which is unique for the MyoVc subclass. Moreover, the cargo- and motor-binding sites were structurally assigned, indicating the conservation of residues involved in the recognition of adaptors for peroxisome transport and providing high resolution insights into motor domain inhibition by CBD. These results contribute to understanding the structural requirements for cargo transport, autoinhibition, and regulatory mechanisms in myosin V motors. (AU)