Special Biology Seminar

A cell's decision to divide is based on information of extra- and intra-cellular origins that is transmitted through specific signaling pathways.  My research aims to determine the dynamic regulatory mechanisms underlying cellular signal processing and computation in relation to the decision to divide. Specifically, we focus on:

1. How cell size triggers division

2. How dynamic input signals are processed to regulate division

3. How the proliferation network evolved across eukaryotes

In this talk, I will focus on our progress in understanding how cell size and growth are coupled to cellular transitions. Cell size is an important physiological trait that is regulated by coupling growth with cell division. Although many of the key regulatory proteins effecting size control have been identified, the underlying molecular mechanisms are unclear. I will discuss our recent progress in addressing this fundamental question in proliferating budding yeast and in developing frog embryos. The common feature of yeast and frog mechanisms is that the synthesis of activating and inhibiting molecules scales differently with cell size. Through this differential size scaling, the ratio of activator and inhibitor becomes a monotonic function of cell size so that the cellular transition becomes size-dependent. Importantly, this mechanism can function in the context of any regulatory network and any cell geometry. Thus, the differential size scaling of macromolecular synthesis provides an elegant mechanism to couple cellular transitions with cell size