Research Report 2010 - MDC

Applications of the tethered toxin and neuropeptide strategy. Endogenous peptide ligands, natural toxins, and synthetic peptides that are modifiedversions of ligands or toxins, can be integrated into recombinant membrane-attached fusion constructs and applied in vitro in transfected ortransduced cells in cell-culture, or in vivo in transgenic or virus-transduced animals. The t-peptide retains the specificity of the toxin/peptide ligandin a region or cell specific expression allowing for controlled manipulation of distinct subtypes of ion channels and receptors in a given neuronalcircuit without affecting other channels/receptors in the cell.Approximately 40 different chimeric t-toxins derivedfrom the venom of several predatory animals havebeen cloned and their activity characterized on voltageand ligand-gated ion channels. The t-peptide strategyhas also been successfully extended to other bioactivepeptides, such as ligand peptides for constitutive activationof GPCRs, illustrating the general applicability ofthis approach for cell-surface modulation of receptors(Figure).Tethered toxins and peptides are being used for verydiverse applications pertaining to experimental animalphysiology. Because of their mode of action at the cellsurface,membrane-anchored peptide molecules actonly on ion channels and receptors present in themembrane of the cell that is expressing the t-toxin or t-peptide, and not on identical receptors present onneighboring cells that do not express the tethered construct.We are applying the t-toxin strategy combinedwith transgenesis and viral-mediated geneticapproaches for investigations regarding the physiologyof neuronal circuits in the mouse nervous system.Selected PublicationsAuer S, Stürzebecher A.S., Jüttner R., Santos-Torres J., Hanack C., FrahmS., Liehl B., Ibañez-Tallon I. Silencing neurotransmission with membranetetheredtoxins. Nature Methods in pressHruska M, Keefe J, Wert D, Tekinay AB, Hulce JJ, Ibañez-Tallon I, Nishi RProstate stem cell antigen is an endogenous lynx1-like prototoxin thatantagonizes alpha7-containing nicotinic receptors and preventsprogrammed cell death of parasympathetic neurons. J Neurosci. 2009Nov 25;29(47):14847-54.Holford M, Auer S, Laqua M, Ibañez-Tallon I. Manipulating neuronalcircuits with endogenous and recombinant cell-surface tetheredmodulators. Front Mol Neurosci. 2009;2:21. Epub 2009 Oct 30.Tekinay AB, Nong Y, Miwa JM, Lieberam I, Ibañez-Tallon I, Greengard P,Heintz N. (2009) A role for LYNX2 in anxiety-related behavior. Proc NatlAcad Sci. 106: 4477-82Miwa J.M., King S. L., Stevens T. R., Caldarone B. J. , Ibañez-Tallon, I,Fitzsimonds R. M., Pavlides C., Picciotto M.R., Heintz N. (2006). Balancingneuronal activity and survival via the cholinergic modulator lynx1.Neuron 51: 587-600Function and Dysfunction of the Nervous System 167