Tomas Kircchausen, PhD Springer Family Chair | Senior Investigator, Program in Cellular and Molecular Medicine (BCH) Harvard University Medical School Research Focus:  Molecular mechanisms that underlie the cells sorting machineries responsible for receptor-mediated endocytosis and for secretion, and how they are highjacked by toxins, viruses and bacterial pathogens to enter cells. We also study how during cell division, cells control their size and organelle architecture.