Fig. 7.

Schematic of the interaction and function of cavins and PP1α in response to stressors. In A431 cells (Cavin2-deficient), hypo-osmotic treatment induces redistribution of cavins and PP1α to the cytosol from plasma membrane caveolae and the nucleus, respectively, to allow interaction of these proteins. In addition, UV treatment led to the dissociation of Cavin3 from caveolae. We propose that the released Cavin3 may interact with the cytosol pool of PP1α first and be subsequently recruited to the nucleus as Cavin3-PP1α complex to associate with γH2AX. In the nucleus, Cavin3 exerts a proapoptotic role by promoting H2AX phosphorylation and its downstream apoptotic signaling through the interaction with and inhibition of PP1α, which has been identified as a direct phosphatase for γH2AX (phospho-H2AX) in this study