Over-expression of Aurora-A targets cytoplasmic polyadenylation element binding protein and promotes mRNA polyadenylation of Cdk1 and cyclin B1

Genes Cells. 2005 Jul;10(7):627-38. doi: 10.1111/j.1365-2443.2005.00870.x.


Aurora-A is a centrosomal serine-threonine kinase that regulates mitosis. Over-expression of Aurora-A has been found in a wide range of tumors and has been implicated in oncogenic transformation. However, how Aurora-A over-expression contributes to promotion of carcinogenesis remains elusive. Immunohistochemical analysis of breast tumors revealed that over-expressed Aurora-A is not restricted to the centrosomes but is also found in the cytoplasm. This over-expressed Aurora-A appeared to be phosphorylated on Thr288, which is known to be required for its enzymatic activation. In analogy to Aurora-A's role in oocyte maturation and the early embryonic cell cycle, here we investigated whether ectopically over-expressed Aurora-A can similarly stimulate polyadenylation of mRNA in human somatic cultured cells by interacting with a human ortholog of cytoplasmic polyadenylation element binding protein, h-CPEB. In vitro experiments revealed that Aurora-A binds directly to, and phosphorylates, h-CPEB. We found that polyadenylation of mRNA tails of cyclin B1 and Cdk1 was synergistically stimulated when Aurora-A and h-CPEB were over-expressed, and they were further promoted in the presence of an Aurora-A activator Ajuba. Our results suggest a function of ectopically over-expressed Aurora-A that might be relevant for carcinogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Aurora Kinase A
  • Aurora Kinases
  • CDC2 Protein Kinase / genetics
  • CDC2 Protein Kinase / metabolism*
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cells, Cultured
  • Cyclin B / genetics
  • Cyclin B / metabolism*
  • Cyclin B1
  • Homeodomain Proteins / metabolism
  • Humans
  • LIM Domain Proteins
  • Molecular Sequence Data
  • Phosphorylation
  • Polyadenylation*
  • Protein Kinases / genetics
  • Protein Kinases / metabolism*
  • Protein Serine-Threonine Kinases
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism*
  • Rats
  • Transcription Factors / metabolism*
  • Xenopus Proteins / genetics
  • Xenopus Proteins / metabolism*
  • mRNA Cleavage and Polyadenylation Factors / metabolism*


  • Ajuba protein, rat
  • CCNB1 protein, human
  • CPEB1 protein, human
  • Ccnb1 protein, rat
  • Cell Cycle Proteins
  • Cyclin B
  • Cyclin B1
  • Homeodomain Proteins
  • LIM Domain Proteins
  • RNA, Messenger
  • Transcription Factors
  • Xenopus Proteins
  • mRNA Cleavage and Polyadenylation Factors
  • Protein Kinases
  • AURKA protein, Xenopus
  • Aurka protein, rat
  • Aurora Kinase A
  • Aurora Kinases
  • Protein Serine-Threonine Kinases
  • CDC2 Protein Kinase