SKP1-SnRK protein kinase interactions mediate proteasomal binding of a plant SCF ubiquitin ligase

Rosa Farrás, Alejandro Ferrando, Ján Jásik, Tatjana Kleinow, László Ökrész, Antonio Tiburcio, Klaus Salchert, Carlos Del Pozo, Jeff Schell, Csaba Koncz

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175 Citations (Scopus)


Arabidopsis Snf1-related protein kinases (SnRKs) are implicated in pleiotropic regulation of metabolic, hormonal and stress responses through their interaction with the kinase inhibitor PRL1 WD-protein. Here we show that SKP1/ASK1, a conserved SCF (Skp1-cullin-F-box) ubiquitin ligase subunit, which suppresses the skp1-4 mitotic defect in yeast, interacts with the PRL1-binding C-terminal domains of SnRKs. The same SnRK domains recruit an SKP1/ASK1-binding proteasomal protein, α4/PAD1, which enhances the formation of a trimeric SnRK complex with SKP1/ASK1 in vitro. By contrast, PRL1 reduces the interaction of SKP1/ASK1 with SnRKs. SKP1/ASK1 is co-immunoprecipitated with a cullin SCF subunit (AtCUL1) and an SnRK kinase, but not with PRL1 from Arabidopsis cell extracts. SKP1/ASK1, cullin and proteasomal α-subunits show nuclear co-localization in differentiated Arabidopsis cells, and are observed in association with mitotic spindles and phragmoplasts during cell division. Detection of SnRK in purified 26S proteasomes and co-purification of epitopetagged SKP1/ASK1 with SnRK, cullin and proteasomal α-subunits indicate that the observed protein interactions between SnRK, SKP1/ASK1 and α4/ PAD1 are involved in proteasomal binding of an SCF ubiquitin ligase in Arabidopsis.

Original languageEnglish
Pages (from-to)2742-2756
Number of pages15
JournalEMBO Journal
Issue number11
Publication statusPublished - Jun 1 2001



  • (PRL1)
  • Arabidopsis Pleiotropic Regulatory Locus 1
  • Proteasome
  • SCF ubiquitin ligase
  • SKP1/ASK1
  • Snf1-related protein kinase

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)

Cite this

Farrás, R., Ferrando, A., Jásik, J., Kleinow, T., Ökrész, L., Tiburcio, A., Salchert, K., Del Pozo, C., Schell, J., & Koncz, C. (2001). SKP1-SnRK protein kinase interactions mediate proteasomal binding of a plant SCF ubiquitin ligase. EMBO Journal, 20(11), 2742-2756.