Principal investigator:

Oecking, Claudia, Prof. Dr.,
Zentrum für Molekularbiologie der Pflanzen (ZMBP)

Abteilung Pflanzenphysiologie

Auf der Morgenstelle 32

72076 Tübingen

Phone: 49 7071 29 76679

E-mail: claudia.oeckingspam prevention@zmbp.uni-tuebingen.de

Summary:

14-3-3 proteins have been implicated in the regulation of diverse biological processes by phosphorylation-dependent protein-protein interactions. Our recently published data indicate that plant 14-3-3 proteins contribute to the subcellular polar localization of PINFORMED (PIN) auxin efflux carriers and consequently auxin transport-related growth. The plasma membrane associated NON PHOTOTROPIC HYPOCOTYL 3 (NPH3) – an essential component of the phototropic signaling pathway – turned out to be a major 14-3-3 target in seedlings and furthermore, seems to require 14-3-3 to fully execute its function. Members of the plant-specific NPH3-like protein family have been suggested to control PIN polarity in response to developmental or environmental signals. Thus, 14-3-3 dependent regulation of NPH3-like proteins might account for development- and environment-driven changes in PIN polarity. We aim at unravelling the molecular determinants and molecular mechanisms underlying NPH3 function. In this respect, the modification of NPH3 in vivo phosphorylation sites as a consequence of signal perception (blue-light) and in the context of its interaction with 14-3-3 proteins will be analyzed. Additionally, we aim to address the importance of the subcellular (polar?) NPH3 localization for its functional specificity as well as for polarity of PIN proteins within the plasma membrane. Altogether, these experiments are expected to contribute to our knowledge on coupling signal input to the establishment of changes in auxin distribution.