Department of Cell Biology
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The Kiebler group studies the localization of mRNAs into dendrites of polarized hippocampal neurons. A set of mRNAs are specifically transported – once exported from the nucleus into the cytoplasm of neurons – with the help of molecular motors along microtubules into processes termed dendrites. These are the receiving units of information in the brain. Once localized to dendrites near synapses, mRNAs will be translated into proteins that allow to structurally and functionally modify activated synapses. This is thought the molecular basis for learning and memory. We are specifically interested in understanding the role of key RNA-binding proteins (RBPs), e.g. Staufen2, Barentsz, Pumilio2 amongst others in dendritic mRNA localization. A second focus is to identify and subsequently study those mRNAs that are transported to synapses, e.g. CaMKIIa (positive control), Rgs4, Calm3. We have reason to believe that defects in dendritic mRNA localization might yield neurological diseases, e.g. spinocerebellar ataxias, epilepsy, Fragile-X-mental retardation. Experimentally, we work with primary cells with a special emphasis on rodent hippocampal neurons in isolated culture, as well as with mice and rats.

The Mayerhofer group studies fundamental questions in human reproductive biology and reproductive medicine, i.e. the functions of the gonads in health and disease (development, infertility, Leydig cell stem cells and spermatogonial stem cells, as well as gonadal cancer cells). Our current research is focused on peritubular cells of the testis and ovarian granulosa cells as models for the human gonads. We collaborate with scientists and clinicians in Germany. Our international partners are located in Finland, Sweden, Chile, Argentina and the United States. Our interdisciplinary approaches include cellular/molecular biological and morphological methods. We are supported by the German Research Foundation (DFG).

The Niessing group studies different processes of posttranscriptional gene regulation. A primary focus is the mechanistic understanding of mRNA localization and localized translation. Here we rely on a model system in budding yeast to study the assembly and activation of an entire transport complex from recombinant factors. In parallel, we also assemble (sub-) complexes of neuronal mRNA-transport factors and solve their high-resolution co-structures. We also aim to understand how mRNA stability is regulated by the binding and activity of transacting proteins. Our scientific toolbox includes protein and RNA biochemistry, quantitative biophysical approaches, X-ray crystallography and Small Angle X-ray Scattering as well as in vivo approaches.

The Müller-Taubenberger group is interested in cell migration in response to chemoattractant gradients, in particular, the mechanisms that regulate cytoskeletal dynamics in Dictyostelium amoebae and neutrophil-like HL60 cells. To analyze directed movement in these systems, they concentrate on the actin and microtubule cytoskeleton in order to explore the signalling networks that are required for the establishment of cell polarity under 2D- and 3D conditions. Current work focuses on three subjects: (i) The role of the actin-crosslinking protein filamin in HL-60 cells; (ii) The functional impact of microtubules and microtubule binding proteins in migration of neutrophils and Dictyostelium; (iii) As post-translational protein modification by arginylation has been shown to be critical for cell motility in other systems, they explore the role of arginylation for migration in Dictyostelium. The experimental tools unsed involve live-cell imaging studies in combination with molecular, biochemical and cell biological methods including microfluidic approaches.

The Dormann group
is focused on the role of RNA-binding proteins in neurodegenerative diseases, especially amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Two RNA-binding proteins (FUS and TDP-43) are abnormally deposited in pathological inclusions in the brains of ALS and FTD patients and play a key role in disease pathogenesis. Previous work by Dorothee Dormann has shown that disturbed nuclear import of FUS and TDP-43 and cellular stress are crucial factors in disease pathogenesis. Currently the Dormann group is studying how FUS and TDP-43 shuttle between the nucleus and cytoplasm, how the two proteins are deposited in pathological protein inclusions and what role they play in the neuronal cytoplasm, specifically in neuronal dendrites.