Motile cilia are vital cellular structures which move in a whip-like manner to propel cells (ex. Sperm cells) or move fluids over tissue surfaces (ex. Moving mucus out of lungs).
Loss of cilia motion leads to a severe lung disease in humans called Primary Ciliary Dyskinesia (PCD). Infants born with PCD have respiratory problems which can develop into fatal lung conditions if not managed. Cilia motion is powered by the coordinated action of thousands of molecular motors called dyneins. The Outer Dynein Arm motors (ODAs) are the main force generators inside cilia and their dysfunction is the most common cause of PCD in humans. PCD remains incurable and to find a cure we need to understand how ODA motors are synthesised and regulated.
I recently discovered a novel conserved inhibitor of ODAs named Shulin using the model organism Tetrahymena thermophila (Mali. et al., 2021). Cryo-electron microscopy revealed that Shulin inactivated ODA motors by locking them into a closed form.
This PhD project aims to characterise in detail the molecular mechanisms of Shulin’s human ortholog - DNAAF9 (Dynein Assembly Factor 9; aka C20ORF194) which is a candidate gene for PCD. This will be addressed by;
1) Using proteomics to identifying novel protein interaction partners of DNAAF9
2) Performing loss-of-function studies using CRISPR knock-out cell-lines for DNAAF9 and/or generating animal models.
3) Biochemically purifying DNAAF9 containing complexes for structural investigations using negative stain and/or cryo electron microscopy and AlphaFold2 protein structure predictions.
The project benefits from an integrative approach combining cell biology with biochemical and structural investigations of a clinically relevant protein, giving the prospective student a unique opportunity to train in a wide breadth of molecular techniques. The project will be supported by excellent research facilities at the University of Bristol (Proteomics and Wolfson Bioimaging facilities and the cryo-electron microscopy facility).