SKP2A protein, an F-box that regulates cell division, is degraded via the ubiquitin pathway

The ubiquitin pathway is emerging as a powerful system that controls the stability of key regulatory proteins. In plants, this pathway plays an important role in controlling several developmental processes, responses to environmental changes and also cell division. Arabidopsis SKP2A is an F-box protein that regulates the stability of the E2FC-DPB transcription factor, a repressor of cell proliferation. Although the function of SKP2A is to recruit targets for degradation, we have shown that SKP2A is also degraded through the Ub/26S pathway and, interestingly, auxin stimulates such degradation. Overexpression of SKP2A positively regulates cell division, increasing the number of cells in G(2)/M, reducing the level of ploidy and developing higher number of lateral root primordia. In addition, we showed in this report that overexpression of SKP2A increased the survival of Arabidopsis plants when they grown on a medium with high levels of sucrose, likely by maintaining cell division active. Thus, it is likely that SKP2A connects cell division with stress responses.