Publications by authors named "Sigurd Ramans-Harborough"
Intrinsic disorder and conformational coexistence in auxin coreceptors.
Proc Natl Acad Sci U S A
October 2023
Article Synopsis
- Auxin/Indole 3-Acetic Acid (Aux/IAA) proteins, such as IAA17/AXR3, act as transcriptional repressors and coreceptors with TIR1/AFB proteins in plant auxin signaling.
- The study employs NMR, circular dichroism (CD), and molecular dynamics (MD) simulations to analyze the N-terminal domains of IAA17/AXR3, revealing a critical W-P bond and a mix of conformations that play a role in auxin perception.
- The findings offer insights into how these proteins interact with TIR1 and highlight the significance of conformational flexibility and intrinsic disorder in auxin signaling pathways.
Peptides derived from non-functional precursors play important roles in various developmental processes, but also in (a)biotic stress signaling. Our (phospho)proteome-wide analyses of C-TERMINALLY ENCODED PEPTIDE 5 (CEP5)-mediated changes revealed an impact on abiotic stress-related processes. Drought has a dramatic impact on plant growth, development and reproduction, and the plant hormone auxin plays a role in drought responses.
View Article and Find Full Text PDFHormonal signalling in animals often involves direct transcription factor-hormone interactions that modulate gene expression. In contrast, plant hormone signalling is most commonly based on de-repression via the degradation of transcriptional repressors. Recently, we uncovered a non-canonical signalling mechanism for the plant hormone auxin whereby auxin directly affects the activity of the atypical auxin response factor (ARF), ETTIN towards target genes without the requirement for protein degradation.
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- Polar auxin transport is essential for plant growth, with PIN-FORMED (PIN) carriers controlling how auxin moves within the plant to influence its development.
- Researchers investigated how auxin affects the movement of PIN proteins and discovered that a compound called pinstatic acid (PISA) enhances this transport in Arabidopsis, impacting growth features like hypocotyl elongation and root formation.
- PISA works by increasing the levels of PIN proteins on the cell surface without activating certain signaling pathways, providing a new tool to explore auxin transport mechanisms further.
Auxin phytohormones control most aspects of plant development through a complex and interconnected signaling network. In the presence of auxin, AUXIN/INDOLE-3-ACETIC ACID (AUX/IAA) transcriptional repressors are targeted for degradation by the SKP1-CULLIN1-F-BOX (SCF) ubiquitin-protein ligases containing TRANSPORT INHIBITOR RESISTANT 1/AUXIN SIGNALING F-BOX (TIR1/AFB). CULLIN1-neddylation is required for SCF functionality, as exemplified by mutants deficient in the NEDD8-activating enzyme subunit AUXIN-RESISTANT 1 (AXR1).
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