Structure and function of the SLAC/SLAH anion channel family

• Applicant: Professor Dr. Rainer Hedrich
• Subject Area: Plant Biochemistry and Biophysics
• Term: from 2009 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 137502288

• Final Report Year: 2015

Final Report Abstract

At the beginning of 2008 SLAC1, the first member of a small gene family in Arabidopsis was identified. Since SLAC1 could not be functionally analysed yet in any heterologous expression system, the structure-function relationship of SLAC/SLAH family members remained unclear. The applicants succeeded to functionally express and analyse members of the SLAC/SLAH family. Using molecular- and biochemical approaches channel function and regulation of major SLAC/SLAH types was determined. Within the SLAC/SLAH anion channel family we identified subtypes differing in anion permeability and gating. Via chimera between these subtypes and mutational analysis we identify channel domains responsible for ion selectivity and voltage control. Based on functional studies with a set of SLAC/SLAH mutants a molecular model of the anion channel complex was generated. The model-predicted channel’s 3D structure fed forward detailed structure-function studies for future testing anion channel biology in planta.

Publications

• (2009). Activity of guard cell anion channel SLAC1 is controlled by drought-stress signaling kinase-phosphatase pair. Proc Natl Acad Sci USA 106, 21425-21430
  Geiger, D., Scherzer, S., Mumm, P., Stange, A., Marten, I., Bauer, H., Ache, P., Matschi, S., Liese, A., Al-Rasheid, K.A., Romeis, T., and Hedrich, R.
  
• (2010). Guard cell anion channel SLAC1 is regulated by CDPK protein kinases with distinct Ca2+ affinities. Proc Natl Acad Sci USA 107, 8023-8028
  Geiger, D., Scherzer, S., Mumm, P., Marten, I., Ache, P., Matschi, S., Liese, A., Wellmann, C., Al-Rasheid, K.A., Grill, E., Romeis, T., and Hedrich, R.
  
• (2010). Stomatal action directly feeds back on leaf turgor: new insights into the regulation of the plant water status from non-invasive pressure probe measurements. Plant J 62, 1072-1082
  Ache, P., Bauer, H., Kollist, H., Al-Rasheid, K.A., Lautner, S., Hartung, W., and Hedrich, R.
  
• (2011). Stomatal closure by fast abscisic acid signaling is mediated by the guard cell anion channel SLAH3 and the receptor RCAR1. Science signaling 4, ra32
  Geiger, D., Maierhofer, T., Al-Rasheid, K.A., Scherzer, S., Mumm, P., Liese, A., Ache, P., Wellmann, C., Marten, I., Grill, E., Romeis, T., and Hedrich, R.
  
• (2012). Ion channels in plants. Physiological reviews 92, 1777-1811
  Hedrich, R.
  
• (2012). Multiple Calcium-Dependent Kinases Modulate ABA-Activated Guard Cell Anion Channels. Molecular plant 5, 1409-1412
  Scherzer, S., Maierhofer, T., Al-Rasheid, K.A., Geiger, D., and Hedrich, R.
  
• (2012). The Stomatal Response to Reduced Relative Humidity Requires Guard Cell-Autonomous ABA Synthesis. Current biology 23, 53–57
  Bauer, H., Ache, P., Lautner, S., Fromm, J., Hartung, W., Al-Rasheid, K.A., Sonnewald, S., Sonnewald, U., Kneitz, S., Lachmann, N., Mendel, R.R., Bittner, F., Hetherington, A.M., and Hedrich, R.
  
• (2013). How do stomata sense reductions in atmospheric relative humidity? Mol Plant. 6: 1703-6
  Bauer, H., Ache, P., Wohlfart, F., Al-Rasheid, K.A., Sonnewald, S., Sonnewald, U., Kneitz, S., Hetherington, A.M., Hedrich, R.
  
• (2014). Site- and kinase-specific phosphorylation-mediated activation of SLAC1, a guard cell anion channel stimulated by abscisic acid. Sci Signal. Sep 9;7(342)
  Maierhofer, T., Diekmann, M., Offenborn, JN., Lind C., Bauer, H., Hashimoto, K., S Al-Rasheid KA, Luan, S., Kudla, J., Geiger, D., Hedrich R.