Title: Structural and functional diversity of calcium-triggered contractile proteins in ciliates

Abstract: Ciliated protozoa employ conventional ATP-powered cytoskeletal motors, such as myosins, dyneins, and kinesins, for motility and intracellular transport. But ciliates also use novel cytoskeletal motors that do not require ATP to generate force. These calcium-triggered motors drive contractile processes, some of which are ultrafast. We are studying the structural and functional properties of three different sets of proteins that form distinct contractile assemblies that exhibit different behaviors. Although these proteins share some conserved features, their architecture, assembly, and response to calcium ions differ. In addition to reconstituting the contractility of these systems with purified proteins, we are beginning the structural analysis of the component proteins and their assemblies using X-ray crystallography, NMR spectroscopy, and cryoelectron microscopy to understand the mechanism of force generation better.

Host: Mary Elting