Macromolecular mobility inside the cell nucleus

The highly organized interior of the living cell imposes major constraints on the dynamic properties of macromolecules and macromolecular complexes in both the cytoplasm and the nucleus. Although there are many examples of cytoplasmic molecular assemblies that can be propelled by molecular motors along microtubules and actin filaments, a view that had emerged during the past few years was that intranuclear mobility results largely from incessant Brownian motion. However, more recent studies now suggest that the movement of an increasing number of macromolecular entities inside the nucleus is controlled by a combination of passive diffusion and ATP-dependent processes.