2015 | 2016 | 2017 | 2018 |


Thu, 01 Jun 2017
Uncovering unknown functions of Ca2+-binding proteins in chloroplast development and signaling

Time: 4.00 PM - 5.00 PM

Venue: Cysteine, Level 7 (30 Biopolis Street, Matrix)

Speaker: Dr. Markus Teige, Department of Ecogenomics and Systems Biology, Faculty of Life Sciences, University of Vienna


Calcium is an important secondary messenger in animal and plant signalling and in plant cells chloroplasts are able to store large amounts of calcium. However, not much is known about the role of calcium in these organelles except for its role as stabilizer of the oxygen-evolving complex at photosystem II (PSII). Chloroplast contain a significant amount of calcium and the total and free Ca2+ concentrations can vary considerably, calling for an involvement of calcium binding proteins in the regulation of such a dynamics. As high concentrations of free Ca2+ inhibit CO2 fixation, it seems plausible that (stromal) calcium binding proteins play a key role in regulating calcium homeostasis in the chloroplast. However, none of those proteins are known for chloroplasts and "classical" Ca2+-binding proteins such as EF-hand proteins could not be experimentally confirmed in this organelle. Therefore, we applied a proteomics approach to identify such components. Here, I will discuss two examples of proteins, with so far unknown function and describe our strategies to identify their function in plant physiology and metabolism. For the first example the LENA protein, we found that these proteins are localized in the chloroplast stroma and bind Ca2+ and demonstrate that they have a strong effect on chloroplast development, photosynthesis, and thylakoid protein phosphorylation. Double knockout or overexpressor plants exhibit slow growth and chlorosis under normal growth conditions as well as altered chloroplast ultrastructure. Unbiased shot-gun proteomics of knockout mutants revealed strongest changes in the levels of photosynthetic proteins and indicate furthermore that retrograde signalling involving GUN proteins is altered in these mutants. In summary, these data suggest that LENA and LENB proteins play an important role in the regulation of chloroplast development and photosynthesis and most likely also other chloroplast processes.

About The Speaker

  • Current position: Group leader Plant Signalling, Ecogenomics & Systems Biology at the University of Vienna (AT)
  • 1992 Diploma in Chemistry Leibniz University of Hannover, Germany
  • 1992-1995 PhD in Biochemistry on regulation of Calvin-cycle enzymes at the IP Gatersleben (DE)
  • 1995-1996 postdoctoral Humboldt fellowship with Paul A. Srere at UT Southwestern, Dallas, TX (USA). Topic: Enzyme complexes of TCA cycle enzymes in yeast mitochondria
  • 1998-2000 Marie Curie individual fellowship with Helmut Ruis at the University of Vienna to study stress responses of yeast and plant cells
  • 2000-2004 Senior postdoc with Heribert Hirt at the University of Vienna to study MAP kinase signalling and stress responses in plants
  • 2002 Habilitation: Venia docendi for Biochemistry from the University of Salzburg
  • Since 2004 Self-funded group leader at the University of Vienna with projects on Ca2+ dependent protein kinases and organellar signalling

Dr. Frank Eisenhaber / Executive Director

Feedback Login Site Map