Currently we are working on the following topics:

Nutrient sensing in plants

How do plant K+ channels sense K+?

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Functional regulation of plant ion channels


Ion channels are mostly multimeric proteins. We are investigating the assembly of these proteins by using diverse methods in vitro and in vivo [1-6]. The model system for these studies are voltage-gated plant potassium channels. Functional channels of this type are built of 4 a-subunits. In 1997 [1] it was proposed that different a-subunits can form hetermeric K+ channels. However, it was not clear whether plants make use of the “heteromerization potential” to increase the diversity of functional K+ channels in a cell. Recently, we could unequivocally proof the existence of heteromeric K+ channels in plants by combining biophysical, mathematical and plant physiological methods [5]. These results may now explain, why some in vivo plant K+ channels differ in their features when compared with heterologously expressed plant K+ channels [7]. Reference [8] summarizes the findings on the assembly of plant K+ channels.

Gating of plant K+ channels

Voltage-gated K+ channels of plants show an astonishing diversity at the functional level. They segregate into 4 groups: (i) inward-rectifying (Kin) channels allow the potassium uptake, (ii) outward-rectifying (Kout) channels allow the potassium release, (iii) weak-rectifying (Kweak) channels allow both, K+ uptake and release, and (iv) silent (Ksilent) potassium channel a-subunits do not form functional channels on their own [9].

In recent studies we could clarify that Kweak channels are in fact specialized Kin channels that react very sensitively towards post-translational modifications [10-12]. Currently, we are exploring the physiological consequences of this regulation in transgenic plants.

Kout channels are characterized by the unique characteristic that they are able to sense the external K+ concentration. They adjust their activity accordingly in order to guarantee that potassium ions are transported only in one direction: out of the cell. The mechanism of this K+-sensing phenomenon could recently be uncovered [13]. It turned out that the K+-sensing mechanism is tightly bound to the voltage-gating of this channel (see above “Nutrient sensing in plants”). This finding might be the key to understand the different voltage-gating of Kin and Kout channels.  In the past and in ongoing studies we are generating chimeras between the Kin channel KAT1 and the Kout channel SKOR [14]. These experimental studies are flanked by computational simulations of the channel structure.

Dynamics of artificial and natural gene-regulatory networks

Another topic of interest of the group is the analysis of the dynamics of gene-regulatory networks [15-17]. Currently, we are designing artificial gene-regulatory networks in eukaryotic cells. The goal is to create cells that react with a special answer to different external stimuli.

… interested? Do not hesitate to contact us or to join us …

We are very open for national and international collaborations.

At the moment we are collaborating with partners from
Colombia, Chile, France, Germany, Italy, Japan, and the UK.

Interested to work in a “global” environment?

Ţ Welcome! Bienvenue! Bienvenidos! Benvenuto! Willkommen!

Heisenberg-Group of Biophysics and Molecular Plant Biology

References (details on the page “Publications”)

[1] Dreyer et al., 1997, Biophys. J. 72:2143-2150; [2] Ache et al., 2001, Plant J. 27:571-580; [3] Dreyer et al., 2004, Biophys. J. 87:858-872; [4] Xicluna et al., 2007, J. Biol. Chem. 282:486-494; [5] Lebaudy et al., 2008a, Plant J. in press; [6] Lebaudy et al., 2008b, PNAS 105:5271-5276; [7] Brüggemann et al., 1999a, PNAS 96:3298-3302; [8] Jeanguenin et al., 2008, Plant Signal Behav 3:9 in press; [9] Dreyer et al., 2004a, In Membrane Transport in Plants, Blatt M.R. (ed). pp 150-192. Oxford, Blackwell; [10] Dreyer et al., 1998, FEBS Lett. 430:370-376; [11] Michard et al., 2005a, Plant J. 44:783-797; [12] Michard et al., 2005b, J. Gen. Physiol. 126:605-617; [13] Johansson et al., 2006, Plant J. 46:269-281; [14] Porée et al., 2005, Biochem.Biophys.Res.Commun. 332:465-472; [15] Riańo-Pachón et al., 2005, Plant J. 43:205-212; [16] Riańo-Pachón et al., 2007, BMC Bioinformatics 8:42; [17] Gómez-Porras et al., 2007, BMC Genomics 8:260.