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Steering neurons through the use of light

9 March 2010. The CEF is pleased to announce that Alexander Gottschalk has just won a Heisenberg Professorship from the Deutsche Forschungs-gemeinschaft (DFG). Alexander Gottschalk is a CEF adjunct investigator and a member of the Institute of Biochemistry at the Goethe University Frankfurt. He studied chemistry in Frankfurt, Marburg and Edinburgh and worked as a postdoc in San Diego (USA) before returning to Germany in 2003. Before winning the Heisenberg-Professorship he has held a junior professorship in molecular membrane biology at the Goethe University for six years. Prof. Gottschalk is married to a pharmacist, and they have three daughters (seven, six and one years old).

Alexander Gottschalk is interested in macromolecular assemblies that function at neuronal synapses to mediate synaptic transmission. This includes both the pre-synaptic compartment, which is where chemical neurotransmitters are released, as well as post-synaptic specializations that receive these chemical signals and elicit a response in the downstream cell. To study these topics, the Gottschalk lab uses the soil nematode Caenorhabditis elegans. Its nervous system consists of exactly 302 neurons. C. elegans is amenable to genetic techniques, and its nervous system can be studied by behavioural analysis, cell biology and electrophysiology.

This minute genetically modified C. elegans worm expresses green fluorescent protein in some neurons. The activitiy of the green fluorescent neurons can be directed through illumination a method which allows detailed study of neuron function.

Proteins involved in neurotransmission are identified by biochemical approaches, for example as part of nicotinic Acetylcholine Receptors. Furthermore, the Gottschalk lab develops and uses optogenetic methods to analyze synaptic transmission, as well as neuronal network function in the generation of behaviour. This approach was developed in collaboration with Ernst Bamberg’s group at the Max Planck Institute of Biophysics in Frankfurt. Light-activated ion-channels and –pumps from microbial origin are expressed in specific neurons of the C. elegans nervous system. By using light of particular colours, these proteins are activated, which depolarizes (=activates) or  hyperpolarizes (=inactivates) these neurons, respectively. This allows the team to study defects in synaptic transmission, both by analyzing photo-evoked behaviours, and by measuring photo-evoked post-synaptic currents. The Gottschalk lab uses automated analysis of photo-evoked worm behaviour to screen the genome for novel factors involved in synaptic vesicle exo- or endocytosis.

Also, by specific expression of the optogenetic tools in specific single neurons, the role of these cells in generating a particular behaviour of the animal is analyzed. This way the team wants to contribute to a better understanding of the function of this anatomically well defined nervous system.

Contact: Professor Alexander Gottschalk, Institute of Biochemistry, Riedberg Campus, Tel: +49 (0) 69 798–29261, a.gottschalk@em.uni-frankfurt.de