Integrated studies on a yeast cytoplasmic RNP localization complex

Dr. Dierk Niessing

Project Summary:

In eukaryotes, asymmetric translocation and translation of cytoplasmic mRNA is a powerful mechanism to achieve cellular asymmetry. Thus far, the best-studied example is the translocation of ASH1 mRNA to the bud tip in the yeast Saccharomyces cerevisiae. For directional transport, ASH1 and more than thirty additional mRNAs are bound by the mRNA-binding protein She2p. She2p interacts with the adapter protein She3p, which binds the myosin V motor protein Myo4p. She3p and Myo4p, but not She2p, are also required for transport of tubular endoplamic reticulum (ER). We recently showed that She2p is a novel type of RNA-binding protein and that transport of mRNPs and ER are coupled. Despite of these insights, little is known about the molecular mechanisms that choreograph directional mRNA transport. In this project we use a combination of X-ray crystallography, biophysical, biochemical, and in vivo approaches to understand the molecular interactions within the cytoplasmic mRNP-core complex. Our ultimate goal is to comprehend how these complexes are assembled, stabilized, and eventually become disassembled again after their transport.

Selected publications (2007-09):
1.    Buschmann, H., Hauptmann, M., Fabri, C., Niessing, D., Lloyd, C.W., Schäffner, A.R.:
Helical growth of Arabidopsis mutant tortifolia2 does not depend on cell division patterns but involves handed twisting of isolated cells.
Plant Cell. Advance Online Publication July 28th (2009)

2.    Du, T.G., Jellbauer, S., Müller, M., Schmid, M., Niessing, D., and Jansen, R.-P.: Nuclear transit of the RNA-binding protein She2p is required for translational control of localized ASH1 mRNA.
EMBO Reports, 9: 781-787 (2008).

3.    Heuck, A., Du, T.-G., Jellbauer, S., Richter, K., Kruse, C., Jaklin, S., Müller, M., Buchner, J.,
Jansen, R.-P., and Niessing, D.: Monomeric myosin V uses two binding regions for the 
assembly of stable translocation complexes. 
Proc. Natl. Acad. Sci. USA - Track II, 105: 19778-19783 (2007).

4.    Müller, M., Heuck, A. and Niessing, D.: Directional mRNA Transport in Eukaryotes: 
lessons from yeast. 
Cell. Mol. Life Sci., 64: 171-180 (2007).