Structure and function of filamentous actin in the cardiac thin filament and in activating platelets, and its role in cardiac disease

This proposal applies state of the art imaging techniques to study the role of Filamentous (F-actin) in cardiac disease.

Firstly, as structural support in striated muscle cells (Aim 1), and secondly, as a dynamic network that adapts quickly to the cell’s requirements in activating platelets (Aim 2).

Aim 1: All proteins in the cardiac (actin based) thin filament can exhibit mutations that cause hypertrophic cardiomyopathy (HCM).

To understand these structure-function-disease relationships we will generate HCM mutant zebrafish (ZF) lines, enabling us directly to understand the effect of disease-causing mutations.

To place our findings in the context of human biology, we will generate the first human native cardiac thin filament structure, using tissue that would otherwise be discarded from cardiac surgical procedures.

Aim 2: F-actin is also instrumental in platelet activation and when inappropriately activated contributes to thrombotic events; we will investigate this important process by studying platelets undergoing activation.

We recently discovered novel conformers of actin residing within the lumen of cytoplasmic microtubules and will explore this arrangement of F-actin in platelets.

Cryo Electron Microscopy (cryo EM) and Tomography (cryo ET) provide unprecedented levels of detail, these high-resolution insights into protein structure will be critical to the development of therapeutics.