2. Some TIR domains can function independently of both EDS1 and catalytic activity, pointing toward possible alternative signalling mechanisms.
3. Protein architecture matters: expressing TIRs in different protein contexts can alter their mechanism. Worth keeping in mind!
So what does this mean?
1. Many non-seed plant TIR domains can signal through EDS1 in N. benthamiana, even though their native lineages lack EDS1...
We then extended this approach to animal and bacterial TIR domains.
Remarkably, the chimeric TIR-NLR architecture was even sufficient to impose EDS1-dependence on a bacterial TIR domain! 🧫
Surprisingly, when we expressed these same TIR domains on a chimeric TIR-NLR scaffold, they reverted to EDS1-dependence.
This suggests that TIR domain mechanism can be influenced by protein architecture.
To investigate this, we expressed TIR-eYFP fusions from across land plant evolution in WT and eds1 N. benthamiana 🌱
Most TIRs were EDS1-dependent. However, some moss and Ginkgo TIR domains functioned independently of both EDS1 and conserved catalytic residues, suggesting alternative mechanisms.
In seed plants, TIR-NLR immune receptors rely on TIR NADase activity to produce small signalling molecules that are perceived by EDS1 to trigger immunity. However, non-seed plants lack EDS1, raising the question: how do their TIR domains function? 🤔
We investigated the EDS1-dependence of TIR domains from across the spectrum of land plant evolution, and found that TIR-NLR architecture itself can influence TIR domain activity, even for animal and bacterial TIRs.
@khongsamchia.bsky.social
Extremely excited to share the first pre-print from my PhD project in the Carella lab, co-first authored with @khongsamchia.bsky.social 🎉 (Thread below ⬇️)
www.biorxiv.org/content/10.6...
Huge thanks to all co-authors and the #CarellaCapybaras for all the support 😊
