Prof. Arpita Upadhyaya from the University of Maryland will be visiting on Oct 9, 2014, and giving a seminar on “Forcing it on: the dynamics of signaling activation in immune cells.”
Abstract:
The activation of lymphocytes is an essential step in the adaptive immune response. Lymphocyte activation involves the binding of specialized receptors with antigen on the surface of antigen presenting cells. This leads to changes in cell morphology and the movement and assembly of receptors, signaling proteins into nanometer-sized complexes called microclusters. These protein assemblies are essential for immune cell activation. While it has long been recognized that the actin cytoskeleton plays an essential role in this process, much of this understanding has focused on biochemical regulation of the actin cytoskeleton. We will summarize our recent studies from a biophysical perspective to explain the mechanistic role of actin in modulating lymphocyte activation. We highlight the roles of actin filaments in exertion of mechanical stresses that support signaling activation, microcluster assembly and movement in T lymphocytes. We have used traction force microscopy to measure the forces exerted by Jurkat T cells during activated spreading. Jurkat T cells are mechanosensitive with cytoskeletal forces and signaling dynamics both sensitive to the stiffness of the surface. We find that these forces are largely due to actin dynamics with myosin motors playing a limited role. Our studies highlight the potential role of cytoskeletal forces in signaling activation.
