Review Article

RhoGTPases as Key Players in Mammalian Cell Adaptation to Microgravity

Figure 1

Central role of the RhoGTPases in the integrated response of mammalian cell to microgravity-related conditions. A growing number of studies are revealing that cells reorganize their cytoskeleton, modulate intracellular tension, and initiate nuclear shapes changes when exposed to conditions of microgravity. Most, if not all, of the structural changes observed on flown cells can be explained by modulation of RhoGTPases, which are mechanosensitive switches. RhoGTPases are known for cytoskeletal dynamics control; nevertheless they are also involved in many other aspects as discussed in this review. We identify general principles dependent on RhoGTPases and define cell sensitivity to gravitational stresses such as oxidative stress, intracellular tension, cell-cell and cell-ECM adhesions, and Wnt/β-catenin pathways. We will try to establish that integrated cellular responses in microgravity are related to specific RhoGTPase activities.