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

Authors

  • Silvia Jurado,

    1. Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria Dpto. Biotecnología (INIA), Carretera de la Coruña Km 7 28 040 Madrid, Spain
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  • Sara Díaz-Triviño,

    1. Centro de Biología Molecular ‘Severo Ochoa’, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Cantoblanco 28 049, Madrid, Spain
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  • Zamira Abraham,

    1. Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria Dpto. Biotecnología (INIA), Carretera de la Coruña Km 7 28 040 Madrid, Spain
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  • Concepción Manzano,

    1. Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria Dpto. Biotecnología (INIA), Carretera de la Coruña Km 7 28 040 Madrid, Spain
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  • Crisanto Gutierrez,

    1. Centro de Biología Molecular ‘Severo Ochoa’, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Cantoblanco 28 049, Madrid, Spain
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  • Carlos del Pozo

    Corresponding author
    1. Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria Dpto. Biotecnología (INIA), Carretera de la Coruña Km 7 28 040 Madrid, Spain
      *(fax +34 913573107; e-mail pozo@inia.es).
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*(fax +34 913573107; e-mail pozo@inia.es).

Summary

Coordination between cell division and cell differentiation is crucial for growth and development of eukaryotic organisms. Progression through the different phases of cell division requires the specific degradation of proteins through the ubiquitin/proteasome 26S (Ub/26S) pathway. In plants, this pathway plays a key role in controlling several developmental processes and responses, including cell proliferation. SKP2A, an F-box protein, regulates the stability of the cell division E2FC-DPB transcription factor. Here, we show that the SKP2A forms a Skp, Cullin containing (SCF) complexin vivo that has E3 ubiquitin ligase activity. Interestingly, SKP2A is degraded through the Ub/26S pathway, and auxin regulates such degradation. SKP2A positively regulates cell division, at least in part by degrading the E2FC/DPB transcription repressor. Plants that overexpress SKP2A increase the number of cells in G2/M, reduce the level of ploidy and develop a higher number of lateral root primordia. Taken together, our results indicate that SKP2A is a positive regulator of cell division, and its stability is controlled by auxin-dependent degradation.

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