Subprojects D02: Plasma membrane-associated response modules involved in cell elongation – specificities versus mutualities
Principal investigators:
Prof. Dr. Klaus Harter
Universität Tübingen
ZMBP, Pflanzenphysiologie
Auf der Morgenstelle 1, 72076 Tübingen
Tel 07071 – 29 72605
Fax 07071 – 29 3287
klaus.harter@zmbp.uni-tuebingen.de
Prof. Dr. Ursula Kummer
Universität Heidelberg
COS, Bioquant
INF 267, 69120 Heidelberg
Tel 06221-54-51278
Fax 06221-54-51483
ursula.kummer@bioquant.uni-heidelberg.de
Prof. Dr. Meixner, Alfred J. ,
Universität Tübingen
Institut für Physikalische und Theoretische Chemie
Auf der Morgenstelle 18
72076 Tübingen
Phone: 49 7071 29 76903
E-mail: alfred.meixner@uni-tuebingen.de
Summary:
Brassinosteroids (BR) and Phytosulfokines (PSK) regulate cell elongation growth in the plant hypocotyl and root. The early events in elongation initiation such as H+ extrusion (apoplastic acidification), hyperpolarization of the plasma membrane potential and wall swelling are gene expression-independent. Our studies in the course of the 1st funding revealed the existence of BR and PSK perceiving response modules in the plasma membrane that consist at least of the ligand-binding receptor [BR insensitive 1 (BRI1) or PSK receptor 1 (PSKR1)], the co-receptor BRI1-associated kinase 1 (BAK1), a P-type proton pump and an ion transporter. The use of our and other´s experimental data allowed the development of a mechanistic computational model. The model reflects the observed cell physiological effects and made predictions of critical parameters for the regulatory factors of the cell physiological responses. Furthermore, we constructed a modern research microscope that combines state-of-the-art spectroscopic methods and super-resolution techniques.
In the up-coming funding period, we aim to elucidate how these two different, specific BR and PSK response modules are able to achieve the very similar response mechanistically. We will determine whether there are specific or more common components in the modules and to which extent the differential spatiotemporal organization and dynamics of the modules in the plasma membrane contribute to specific signaling and their cell physiological functions.
The experimental data will be used to develop and integrate a computational model for the response pathway of the PSKR1 response module. Furthermore, we will expand the already developed model of the BRI1 response pathway and the new model of the PSKR1 response modul by a spatial dimension. With this spatiotemporal model of the root with cellular resolution we aim to quantitatively predict elongation in response to either or both stimuli.