Milan MrksichView all speakers
Milan Mrksich is the Henry Wade Rogers Professor at Northwestern University, with appointments in Biomedical Engineering, Chemistry and Cell & Molecular Biology. He attended the University of Illinois, earning a BS degree in Chemistry, his PhD at Caltech and was an American Cancer Society Postdoctoral Fellow Harvard University before joining the faculty at the University of Chicago as an Assistant Professor in 1996.
Among his many honors are the Camille Dreyfus Teacher-Scholar Award (2000), the TR100 Young Innovator Award (2002), ACS Arthur C. Cope Young Scholar Award (2003), and election to the American Association for the Advancement of Science (2006). His research program lies at the intersection of chemistry, materials and biology and emphasizes the design and preparation of materials for applications in chemical biology and bioanalytical science. He has served on the Scientific Advisory Boards of several life sciences companies.
The reactions of molecules in the cell occur in highly non-uniform settings. Enzymes, cofactors, and substrates are rarely present at uniform concentrations throughout the cell but rather are spatially organized into regions of high and low concentration. These concentration profiles and the ways in which they are temporally regulated are essential to the normal operation of the reaction networks that underlie cell function. Yet, mechanistic studies of the unique factors that stem from spatio-temporal structuring of reactants are challenging. This seminar will describe a model system wherein enzymes act on immobilized substrates, with several unusual features. We show that a kinase which can associate with the phosphopeptide it generates will display an autocatalytic reaction profile. Further, the reaction generates spatial patterns of the product and shows an initial rate that varies with geometrical pattern, but not the ratio, of substrate and product. When reactions are performed in the presence of an opposing phosphatase, the direction of the phosphorylation reaction shows a dependence on the density of the substrate. This last observation points to a new motif for regulating phosphorylation events at the cell membrane and we engineer cells that display a kinase-dependent transmembrane signaling event in response to clustering of a chimeric receptor. This work provides an example of the unique features that derive from biochemical reactions in non-uniform environments.