Impact of cellular geometry on nuclear dynamics

Abstract

Nuclear movement or dynamics is required for various physiological functions including migration, mitosis, polarization and fertilization. Recent experiments have revealed that different cytoskeletal components and molecular motors are involved in nuclear movement when cell is exposed to different external stresses like shear stress, stretching or wound healing. However, the mechanism of nuclear movement in a stationary cell under normal physiological conditions still remains unclear. In this work, we first observe and characterize the role of cell shape on nuclear dynamics and further investigate the role of cytoskeletal proteins and its associated motors to determine the mechanism involved. Using the fibronectin coated micropatterned substrate of various geometry, we could confine the cells to a particular area and engineer its shape: symmetrical and asymmetrical. Our findings indicate that the cell shape indeed affects the nuclear movement, as characterized by its rotation and translocation dynamics. Further, using drugs for inhibition of acto-myosin contractility and dynein motor we find that nuclear rotation is a consequence of active cytoskeleton around the nucleus.