19-BBSRC-NSF/BIO. Leveraging synthetic biology to probe the rules of cell morphogenesis.

This project seeks to understand how cells control their shape and movement using synthetic tools. Cell movement is essential for single cells to hunt and mate and for the correct development and function of multicellular organisms. Sheet-like protrusions called lamellipodia are the engines that power and guide this motility. However, the rules of their formation are not understood. Similar to ant colonies where no individual is "in charge", and the overall behaviours of a colony depends on simple rules of local interaction between ants, many aspects of cell biology are dominated by local rules of interaction between proteins. This project seeks to define these rules of protein-protein interactions by constructing lamellipodia from synthetic, designer proteins whose patterns of interaction can be built to order. This work is a collaboration between an expert in cell shape/movement (Weiner) and an expert in protein design (Woolfson). This work is necessarily multidisciplinary and it will train three postdoctoral fellows to work together across cell biology, protein design and biophysics. This work will strengthen links between US and UK labs and between the NSF and the BBSRC.

Weiner's lab recently discerned the nanoscale organization of a key actin nucleator that suggests a self-organizing template for lamellipodia formation. These templates are not sufficiently understood to manipulate directly their biophysical parameters (such as linearity vs. curvature, rigidity, dynamics, etc.) and to probe fully the relation between actin nucleator oligomerization and cell shape and function. A powerful alternative to the typical genetic and biochemical approaches would be to build actin regulators from scratch, so that the molecular logic of cell shape and movement can be probed systematically. To do this, protein engineering and de novo protein design (Woolfson lab) will be used to generate synthetic proteins that assemble with defined geometries at membranes to nucleate actin, guided by our knowledge of the native system. These synthetic systems will be tested for their ability to support lamellipodial formation in vivo using cells defective in lamellipodia formation and ultimately in complete reconstitutions. These studies will advance protein design towards in-cell application, and, in turn, they will help define the molecular logic of cell shape and movement.