ChBE Seminar Series: Arpita Upadhyaya
Tuesday, April 8, 2014
11:00 a.m.-12:00 p.m.
Room 2108, Chemical and Nuclear Engineering Building
Professor Ganesh Sriram
Push, Pull and Sense: How Forces Modulate Cellular Dynamics
Department of Physics and IPST
University of Maryland, College Park
Cells interact with their environment during diverse biological processes ranging from the immune response to large-scale organization of tissues during development. In addition to intricate genetic programs, these processes are also regulated by physical cues such as the rigidity, topography and fluidity of cells and their environment. Cells sense these physical attributes by spatially and temporally organizing internal components such as biopolymers or collections of proteins on their surface and by changing shape and exerting forces. Understanding how different types of biological cells have the capability of generating and sensing mechanical forces is an important challenge with fundamental implications for physics and biology. The active mechanical behavior of cells is mediated by actin, a semi-flexible biopolymer organized into contractile networks by a variety of cross-linking and motor proteins, which are maintained far from thermal equilibrium by active co nsumption of energy. We present our investigations of actin-mediated force generation and active sensing in two different cell types: immune cells and cells of the cancer microenvironment. We show that despite striking differences in the molecular details, both types of cells exhibit the ability to sense the rigidity of their environment. We relate our observations to phenomenological models of active gels which predict that rigidity sensing is a large-scale mechanism involving cell-wide ordering of biopolymer filaments. Our studies provide insight into the design principles of adaptive biological matter.