Many plants produce enzymes collectively known as ribosome-inactivating proteins (RIPs). RIPs catalyze the removal of an adenine residue from a conserved loop in the large ribosomal RNA. The adenine residue removed by this depurination is crucial for the binding of elongation factors. Ribosomes modified in this way are no longer able to carry out protein synthesis. Most RIPs exist as single polypeptides (Type 1 RIPs) which are largely non-toxic to mammalian cells because they are unable to enter them and thus cannot reach their ribosomal substrate. In some instances, however, the RIP forms part of a heterodimer where its partner polypeptide is a lectin (Type 2 RIPs). These heterodimeric RIPs are able to bind to and enter mammalian cells. Their ability to reach and modify ribosomes in target cells means these proteins are some of the most potently cytotoxic poisons found in nature, and are widely assumed to play a protective role as part of the host plant’s defenses. RIPs are able to further damage target cells by inducing apoptosis. In addition, certain plants produce lectins lacking an RIP component but which are also cytotoxic. This book focuses on the structure/function and some potential applications of these toxic plant proteins.
Plant Cell Monographs Volume 18 Series Editor: David G. Robinson Heidelberg, Germany For further volumes: http://www.springer.com/series/7089 Plant Cell Monographs Recently Published Titles Toxic Plant Proteins Volume Editor: Lord, J. M., Hartley, M. R. Vol. 18, 2010 Cell Division Control in Plants Volume Editors: Verma, D. P. S., Hong, Z. Vol. 9, 2008 Cell Biology of Metals and Nutrients Volume Editor: Hell, R., Mendel, R. R. Vol. 17, 2010 Endosperm Volume Editor: Olsen, O.-A. Vol. 8, 2007 Lipid Signaling in Plants Volume Editor: Munnik, T. Vol. 16, 2010 Nitric Oxide in Plant Growth Development and Stress Physiology Volume Editors: Lamattina, L., Polacco, J. Vol. 6, 2007 Cell Biology of Plant Nematode Parasitism Volume Editor: Berg, R. H., Taylor, C. G. Vol. 15, 2009 Functional Organization of the Plant Nucleus Volume Editor: Meier, I. Vol. 14, 2009 The Chloroplast Interactions with the Environment Volume Editors: Sandelius, A. S. Aronsson, H. Vol. 13, 2009 Root Hairs Volume Editors: Emons, A. M. C. Ketelaar, T. Vol. 12, 2009 Plant Microtubules Development and Flexibility 2nd Edition Volume Editor: Nick, P. Vol. 11, 2008 Plant Growth Signalling Volume Editors: Bo¨gre, L., Beemster, G. Vol. 10, 2008 The Expanding Cell Volume Editors: Verbelen, J.-P., Vissenberg, K. Vol. 5, 2007 The Plant Endoplasmic Reticulum Volume Editor: Robinson, D. G. Vol. 4, 2006 The Pollen Tube A Cellular and Molecular Perspective Volume Editor: Malho´, R. Vol. 3, 2006 Vol. 5/L, 2006 Somatic Embryogenesis Volume Editors: Mujib, A., Samaj, J. Vol. 2, 2006 Plant Endocytosis Volume Editors: Sˇamaj, J., Balusˇka, F., Menzel, D. Vol. 1, 2005 J. Michael Lord l Martin R. Hartley Editors Toxic Plant Proteins Editors Dr. J. Michael Lord University of Warwick Dept. Biological Sciences CV4 7AL Coventry United Kingdom
[email protected] Dr. Martin R. Hartley University of Warwick Dept. Biological Sciences CV4 7AL Coventry United Kingdom
[email protected] Series Editor Professor Dr. David G. Robinson Ruprecht-Karls-University of Heidelberg Heidelberger Institute for Plant Sciences (HIP) Department Cell Biology Im Neuenheimer Feld 230 69120 Heidelberg Germany