Event DetailsEvent Dates: Monday, March 9, 2015 - 4:00pmSeminar Location: Duane Physics Room G1B30Speaker Name(s): Karen KaszaSpeaker Affiliation(s): Zallen lab, Memorial Sloan Kettering Cancer Center Seminar Type/SubjectScientific Seminar Type: Physics Department ColloquiumEvent Details & Abstract: The ability of multicellular tissues to physically change shape, move, and grow is a key feature of life. These processes are often accomplished by local movements or rearrangements of cells within the tissues. Many cell movements are actively driven by contractile forces generated in cells by the motor protein myosin II. During embryonic development, forces are patterned to orient cell movements, resulting in changes in tissue shape that build functional tissues and organs. To uncover how force-generation by myosin drives cell movement and determines the physical behavior of tissues, I use the fruit fly embryo as a model system, where polarized patterns of myosin activity orient cell movements and rapidly elongate the embryo. I will discuss how studying embryos made with engineered myosin variants allows us to dissect mechanisms underlying tissue behavior. In particular, I will describe how myosin variants with enhanced activity accelerate cell movement but, surprisingly, also alter the spatial pattern of forces and result in reduced tissue elongation. These experiments reveal that the levels and patterns of forces are controlled by the same biological cue and suggest a trade-off between the speed and orientation of cell movements within tissues. These studies of how forces shape the fruit fly embryo shed light not only on physical principles at work in active, living materials but also on how defects in cell movements contribute to human birth defects and tumor metastasis.