Biology subjects

Oecking, C.

Publications and source records attributed to Oecking, C..

3 recordsLinked to original sources

bioRxiv2025

An ancient alkalinization factor informs Arabidopsis root development

The power of hydrogen (pH) regulates virtually all cellular activities. In both plants and animals, cell-to-cell variations in pH correlate with key developmental transitions1-5, yet the underlying regulators and associated functions remain elusive. Here, we report that members of the REMORIN (REM) protein family function as inhibitors of the H+-ATPases thereby promoting extracellular pH (pHe) alkalinization. This, in turn, regulates various cell surface processes, including steroid hormone signaling, and coordinates developmental transitions in the Arabidopsis thaliana root. Inhibition of H+-ATPases by REMs represents an evolutionary innovation that predates the origin of the root system itself. This study thus uncovers an ancient alkalinization mechanism co-opted by the root developmental program and infers that pHe patterning may have shaped morphogenesis evolution.

plant biology↗

bioRxiv2024

AI-assisted decoding of molecular signatures essential for condensation and function of NON-PHOTOTROPIC HYPOCOTYL3

The plasma membrane-associated protein NON-PHOTOTROPIC HYPOCOTYL 3 (NPH3) is a key component of plant phototropism. Blue light induces the release of NPH3 into the cytosol, where it dynamically transitions into membrane-less biomolecular condensates. Here, we combine experimental data with the power of AI-based protein structure prediction to uncover a bipartite C-terminal motif that enables self-interaction of NPH3. We further demonstrate its importance for both the association of NPH3 with the plasma membrane and the assembly of condensates in the cytosol, with a different part of the bipartite motif playing the key role in each case. However, the formation of cytosolic condensates additionally requires the co-operative action of an N-terminal NPH3 signature. We propose that NPH3 forms a crosslinked 3D network in the cytosol based on distinct molecular determinants that simultaneously self-associate. NPH3 variants incapable of condensation are non-functional, suggesting a fundamental role of NPH3 phase separation for phototropism. This structural snapshot could have direct implications for future analyses of the plant-specific NPH3/RPT2-Like protein family.

plant biology↗

bioRxiv2021

Light-triggered and phosphorylation-dependent 14-3-3 association with NONPHOTOTROPIC HYPOCOTYL 3 is required for hypocotyl phototropism

NON-PHOTOTROPIC HYPOCOTYL 3 (NPH3) is a key component of the phototropic response, acting downstream of the primary photoreceptor phototropin and upstream of auxin redistribution. Despite the obvious physiological significance of the blue light-induced differential growth process, the molecular mode of NPH3 action is poorly understood. Light-triggered dephosphorylation of NPH3, however, is thought to constitute a major signaling event. Here, we show that NPH3 directly binds to polyacidic phospholipids via a polybasic motif in its C-terminal domain, allowing for plasma membrane association in darkness. We further demonstrate that blue light induces phosphorylation of a C-terminal 14-3-3 binding motif in NPH3. Subsequent binding of 14-3-3 to the phosphorylated NPH3 in turn is required for light-triggered release of NPH3 from the plasma membrane. In the cytosol, NPH3 undergoes a dynamic transition from a dilute to a condensed state. Intriguingly, the dephosphorylated state of the 14-3-3 binding site as well as NPH3 plasma membrane association are recoverable in darkness. Given that NPH3 variants constitutively localizing either to the plasma membrane or to cytosolic condensates are non-functional, the phototropin-triggered and 14-3-3 mediated dynamic change in the subcellular localization of NPH3 seems to be crucial for its function. Taken together, our data demonstrate a fundamental role for 14-3-3 members in regulating NPH3 localization and auxin-dependent phototropic responses.

plant biology↗