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

Abstract

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 G₂/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.

Addendum to: Jurado S, Díaz-Triviño S, Abraham Z, Manzano C, Gutierrez C, Del Pozo C. SKP2A, an F-box protein that regulates cell division, is degraded via the ubiquitin pathway. Plant J 2008; 53:828-41.

Figures and Tables

Figure 1 SKP2A expression level is increased during osmotic stress. Taken from http://www.bar.utoronto.ca/.18

Figure 2 SKP2A overexpression increased the percentage of plants that survived when grown in high concentration of sucrose. Control and SKP2A^OE plants were grown on MS medium with different concentration of sucrose during 14 days. SKP2A overexpression increased plant survival when they are grown in a MS medium with 5% or 7% of sucrose. All plants survived when they were grown in MS medium with 1% or 3% (data not shown).

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