SAMBA, a plant-specific anaphase-promoting complex/cyclosome regulator is involved in early development and A-type cyclin stabilization

Proc Natl Acad Sci U S A. 2012 Aug 21;109(34):13853-8. doi: 10.1073/pnas.1211418109. Epub 2012 Aug 6.


The anaphase-promoting complex/cyclosome (APC/C) is a large multiprotein E3 ubiquitin ligase involved in ubiquitin-dependent proteolysis of key cell cycle regulatory proteins, including the destruction of mitotic cyclins at the metaphase-to-anaphase transition. Despite its importance, the role of the APC/C in plant cells and the regulation of its activity during cell division remain poorly understood. Here, we describe the identification of a plant-specific negative regulator of the APC/C complex, designated SAMBA. In Arabidopsis thaliana, SAMBA is expressed during embryogenesis and early plant development and plays a key role in organ size control. Samba mutants produced larger seeds, leaves, and roots, which resulted from enlarged root and shoot apical meristems, and, additionally, they had a reduced fertility attributable to a hampered male gametogenesis. Inactivation of SAMBA stabilized A2-type cyclins during early development. Our data suggest that SAMBA regulates cell proliferation during early development by targeting CYCLIN A2 for APC/C-mediated proteolysis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Anaphase-Promoting Complex-Cyclosome
  • Arabidopsis / genetics*
  • Arabidopsis / metabolism*
  • Cell Cycle
  • Cyclin A / chemistry*
  • Gene Expression Regulation, Plant
  • Models, Biological
  • Models, Genetic
  • Molecular Sequence Data
  • Mutation*
  • Phenotype
  • Plant Leaves / metabolism
  • Plant Proteins / metabolism
  • Pollen / metabolism
  • Sequence Homology, Amino Acid
  • Ubiquitin-Protein Ligase Complexes / genetics
  • Ubiquitin-Protein Ligase Complexes / physiology*


  • Cyclin A
  • Plant Proteins
  • Ubiquitin-Protein Ligase Complexes
  • Anaphase-Promoting Complex-Cyclosome