Deconstruction and reconstruction of cell polarity networks

Cell polarity is necessary for diverse processes during animal development. A hallmark of polarized metazoan cells is the segregation of partitioning-defective (PAR) proteins into distinct compartments at the cell cortex. The design principle that governs local molecular interactions among PAR proteins into global cellular patterning remains elusive. With C. elegans zygotes as a model system, we will present our findings on 1) the mechanisms underlying symmetry breaking by sperm-donated centrosome, and 2) how physical properties of the cell cortex ensures segregation of PAR proteins. Based on these findings from genetic assays, we re-constructed the molecular circuits in PAR polarity network in a non-metazoan cell system. Our findings provide the simplest network that executes self-organized polarization, which will permit synthetic control of cell polarity programs in living cells.