Importantly, this research would not have been possible without funding from DFG, IRTG2466, CEPLAS & CRC1535

👀 Feedback and comments are warmly welcome!
@biorxivpreprint.bsky.social #GPCR #FungalBiology #PlantPathology #PhDLife

I’m so grateful to the amazing @faltegoer.bsky.social team behind this work, and big thanks to our international collaborators:

- Min & @billerbecks.bsky.social. Peptide–GPCR screening (Imperial College London)
- Orlando & Manav. Single-cell tracking & quantitative biology (NC State University)

The Gpe1–Pit2 system is conserved in smut fungi, suggesting a co-evolutionary arms race. A hint towards a broader relevance of peptide communication in fungi? We will find out, stay tuned!
(4/5)

The system mimics the fungal pheromone signaling pathway (Ste2 in yeast). But with a twist: host enzymes control the activation.
(4/5)

We solved the crystal structure of Pit2 and found that it forms a homodimer that buries the activating peptide.

This explains why Gpe1 is only activated after host entry — a beautifully designed infection switch by nature, which drives fungal proliferation
(3/5)

The story begins with Pit2, a previously described secreted protein from U. maydis. Once inside the plant, Pit2 is cleaved by apoplastic host proteases (PLCPs), releasing a hidden peptide.

This peptide directly activates Gpe1 — a previously uncharacterized GPCR and Pit2 genomic neighbour.
(2/5)

🧵How does a pathogen know it has entered its host?

New preprint!🎉It’s a pleasure to share my first first-author preprint from my PhD journey!
We uncover a novel co-evolved peptide–GPCR system in the fungus Ustilago maydis that senses host entry and triggers infection (doi.org/10.1101/2025...)
(1/5)