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Biology subjects

Stone, C. E.

Publications and source records attributed to Stone, C. E..

3 recordsLinked to original sources

Computational design of de novo integrated domains enables rational control of pathogen effector recognition in plant NLR immune receptors.

The rapid evolution of plant pathogens poses a persistent threat to global agricultural sustainability, often outpacing the discovery and deployment of natural disease resistance genes. While bioengineering of plant intracellular immune receptors (NLRs) offers a potential solution, developing bespoke immune recognition remains constrained by the laborious characterisation of natural receptors and plant-pathogen interactions. Here, we describe a programmable framework that leverages generative AI protein design tools, RFdiffusion and ProteinMPNN, to design de novo integrated domains (IDs) against diverse pathogen effectors. By integrating these bespoke binders into the modular rice blast Pik-1/Pik-2 NLR receptor chassis, we successfully engineer recognition of a non-cognate virulence factor (effector) from the Panama disease pathogen, Fusarium oxysporum f. sp. cubense Tropical Race 4. Functional assays in Nicotiana benthamiana demonstrate that these de novo domains facilitate specific effector perception and initiate immune signalling, while structural and biophysical analyses confirm that de novo integrated domains maintain high structural fidelity to the initial designs and associate with their targets via the predicted interaction interfaces. Additionally, our findings provide orthogonal evidence for the role of integrated domains in regulation of NLR signalling, demonstrating integration of de novo IDs can either trigger autoactivity or, in some cases, lead to effector-mediated repression of cell death. By decoupling immune perception from natural evolutionary history through deploying AI-designed sensory domains, this work establishes a design-lead framework for generation of programmable plant immune receptors, providing a new avenue for bioengineering crops against emerging pathogens.

plant biology↗

KIF1C activates and extends dynein movement through the FHF cargo adaptor

Cellular cargos move bidirectionally on microtubules due to the presence of opposite polarity motors dynein and kinesin. Many studies show these motors are co-dependent, whereby one requires the activity of the other, although the mechanism is unknown. Here, using in vitro motility assays, we show that the kinesin-3 KIF1C acts both as an activator and a processivity factor for dynein. Activation only requires a fragment of the non-motor tail of KIF1C (KIF1C-stalk) to bind the cargo adaptor HOOK3. Cryo-EM, crosslinking mass spectrometry and AlphaFold2 predictions reveal this binding site to be separate from that of two constitutive factors (FTS and FHIP), which link HOOK3 to small G-proteins on cargos. We provide a structural model for how the FTS-HOOK3-FHIP1B (FHF) complex is auto-inhibited and explain how the KIF1C-stalk relieves this inhibition. Collectively, our work provides a molecular explanation for co-dependency by revealing that the mutual activation of dynein and kinesin is mediated through their shared adaptor. Many adaptors bind both dynein and kinesins, suggesting this mechanism could be generalised to other bidirectional complexes.

cell biology↗

The Arp1/11 Minifilament of Dynactin Primes the Endosomal Arp2/3 Complex

Dendritic actin networks develop from a first actin filament through branching by the Arp2/3 complex. At the surface of endosomes, the WASH complex activates the Arp2/3 complex and interacts with the Capping Protein for unclear reasons. Here we show that that the WASH complex interacts with Dynactin and uncaps it through its FAM21 subunit. In vitro, the uncapped Arp1/11 minifilament elongates an actin filament, which then primes the WASH-induced Arp2/3 branching reaction. In Dynactin-depleted cells or in cells where the WASH complex is reconstituted with a FAM21 mutant that cannot uncap Dynactin, formation of branched actin at the endosomal surface is impaired. Our results reveal the importance of the WASH complex in coordinating two complexes containing actin-related proteins. One Sentence SummaryDendritic actin networks grow in an autocatalytic manner starting from the uncapped minifilament of Dynactin.

cell biology↗