title: Biological and antipathogenic activities of ribosome-inactivating proteins from Phytolacca dioica L.
abstract: BACKGROUND
  The species from the genus Phytolacca constitute one of the best sources of ribosome-inactivating proteins (RIPs) that have been used both in the therapy against virus and tumors and in the construction of transgenic plants resistant to virus, bacteria, fungi and insects. Here we investigate new activities of three representative RIPs from Phytolacca dioica (dioicin 2, PD-S2 and PD-L4).
  
  
  RESULTS
  The three RIPs displayed, in addition to already reported activities, rRNA N-glycosylase activities against plant, bacterial and fungal ribosomes. Additionally dioicin 2 and PD-L4 displayed endonuclease activity on a supercoiled plasmid DNA, and dioicin 2 and PD-S2 arrested the growth of the fungus Penicillium digitatum. Furthermore, dioicin 2 induced caspase activation and apoptosis in cell cultures.
  
  
  CONCLUSIONS
  The different activities of the RIPs from Phytolacca dioica may explain the antipathogenic properties attributed to these RIPs in plants and their antiviral and antitumoral effects. In spite of the similarity in their rRNA N-glycosylase and DNA polynucleotide:adenosine glycosylase activities, they differed in their activities against viral RNA, plasmid DNA, fungi and animal cultured cells. This suggests that the presence of isoforms might optimize the response of the plant against several types of pathogens.
  
  
  CONCLUSIONS
  RIPs from Phytolacca can induce plant resistance or tumor cell death not only by means of ribosome inactivation but also by the activities found in this report. Furthermore, the induction of cell death by different mechanisms turns these RIPs into more useful tools for cancer treatment rendering the selection of RIP-resistant mutants impossible.
authors.affiliation: Department of Biochemistry and Molecular Biology and Physiology, Faculty of Sciences, University of Valladolid, E-47011 Valladolid, Spain.
authors.forename: Rosario
authors.initials: R
authors.lastname: Iglesias
authors.affiliation: Department of Biochemistry and Molecular Biology and Physiology, Faculty of Sciences, University of Valladolid, E-47011 Valladolid, Spain.
authors.forename: Lucía
authors.initials: L
authors.lastname: Citores
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, I-81100 Caserta, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Ragucci
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, I-81100 Caserta, Italy.
authors.forename: Rosita
authors.initials: R
authors.lastname: Russo
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, I-81100 Caserta, Italy. Electronic address: antimo.dimaro@unina2.it.
authors.forename: Antimo
authors.initials: A
authors.lastname: Di Maro
authors.affiliation: Department of Biochemistry and Molecular Biology and Physiology, Faculty of Sciences, University of Valladolid, E-47011 Valladolid, Spain. Electronic address: rosario@bio.uva.es.
authors.forename: José M
authors.initials: JM
authors.lastname: Ferreras
mesh_terms: D000595:Amino Acid Sequence; D004720:Endonucleases / Q000378:metabolism; D008969:Molecular Sequence Data; D010407:Penicillium / Q000187:drug effects; D029603:Phytolacca / Q000737:chemistry*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D054788:Ribosome Inactivating Proteins / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D011500:Protein Synthesis Inhibitors; D004720:Endonucleases; D054788:Ribosome Inactivating Proteins
keywords: Antifungal; Antiviral; Apoptosis; Endonuclease; Polynucleotide:adenosine glycosylase; rRNA N-glycosylase