Schmitt, Hans Dieter, Dr.
Research Group Leader at the MPI for Biophysical Chemistry
- 1983 Dr. rer. nat., TH Darmstadt, Germany
- 1984-1986 Postdoc, Philipps University Marburg, Germany
- 1987-2005 Department of Molecular Genetics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- 2001 Habilitation (Genetics), University Kassel, Germany
- Since 2006 Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen
- Since 2010 leader of the research group ‘Membrane Transport in Yeast’ (same institute)
Major Research Interests
Membrane transport in eukaryotes is mediated by carriers like vesicles and tubules. Several protein complexes are required to control and catalyze the fusion of these carriers with the appropriate target membranes. Each cell is equipped with several sets of these proteins and protein complexes. Each one is specific for a different transport step (e.g. endoplasmic reticulum [ER] to Golgi or Golgi to plasma membrane transport). Among these specific sets of proteins the SNAREs represent the best characterized protein family. They act as membrane-anchored receptors present on opposing membranes. They contribute to the specificity in membrane docking and catalyze membrane fusion. SNAREs get help by a heterogeneous group of proteins and complexes, the so-called tethering factors. Tethering factors are believed to form a bridge between the approaching membranes and act before or together with the SNAREs.
Most tethering complexes outside the Golgi apparatus consist of many subunits. Eight of these multi subunit tethering complexes (MTCs) were discovered so far. Our group works on the simplest MTC, the Dsl1 complex in the yeast Saccharomyces cerevisiae. As it mammalian counterpart, the syntaxin 18 complex, the Dsl1 complex consists of only three subunits. They are closely associated with the ER-localized SNAREs. Dsl1p, the biggest subunit of this complex, interacts with the coat proteins (COP-I) that cover the Golgi-derived vesicles. This may help to direct the COP-I vesicles to the right sites for fusion, the ER. Switching off DSL1 expression leads to the accumulation of large amounts of COP-I-coated vesicles mainly at one prominent ER exit site. The vesicle clusters are readily dissolved after switching on DSL1 expression again. The structure of the complex has recently been determined (Ren et al., 2009; Cell 139:1119-29). This showed that the whole complex is ideally designed to link SNAREs and coated vesicles. The questions we address in our current work are: (i) Why do the vesicles accumulate at one site within the cell? (ii) Is the Dsl1 complex involved in the uncoating of the vesicles. (iii) Which other proteins are involved in the tethering/docking reaction?
Homepage Department / Research Group
Selected Recent Publications
- Schmitt, HD (in press) Dsl1p/Zw10: common mechanisms behind tethering vesicles and microtubules. Trends Cell Biol 10, 257-268
- Zink S, Wenzel D, Wurm CA, Schmitt HD (2009) A link between ER tethering and COP-I vesicle uncoating. Dev Cell 17, 403-416
- Kraynack BA, Chan A, Rosenthal E, Essid M, Umansky B, Waters MG, Schmitt HD (2005) Dsl1p, Tip20p, and the Novel Dsl3(Sec39) protein are required for the stability of the Q/t-SNARE complex at the endoplasmic reticulum in yeast. Mol Biol Cell 16, 3963-3977
- Andag U, Schmitt HD (2003) Dsl1p, an essential component of the Golgi-endoplasmic reticulum retrieval system in yeast, uses the same sequence motif to interact with different subunits of the COPI vesicle coat. J Biol Chem 278, 51722-51734
- Andag U, Neumann T, Schmitt HD (2001) The coatomer interacting protein Dsl1p is required for Golgi-to-ER retrieval in yeast. J Biol Chem 276, 39150-39160