Biology subjects

Kirk, P.

Publications and source records attributed to Kirk, P..

4 recordsLinked to original sources

bioRxiv2026

Prefrontal brain-to-brain synchrony during human group hunting: Evidence from fNIRS hyperscanning

Orca, wolves, chimpanzees and humans share a similarly impressive capacity for group hunting, where individuals coordinate behaviour together to capture prey. Studying hunting behaviours has important implications for understanding how behaviour in group contexts may be indicative of cognitive decline. Despite growing interest in brain circuits for prey capture, the brain regions involved in tracking prey during a hunt and the behaviours in group hunt linked to success remain unclear. Here we combined functional near infrared spectroscopy (fNIRS) and a virtual minecraft world to examine behaviour, brain dynamics and brain synchrony involved in group hunting behaviour. We focused on the prefrontal cortex (PFC) due to its known role in planning and social coordination and recorded from pairs of individuals as they either cooperated to hunt another person (prey) or simply followed another person. Hunters were more successful if they managed to keep a smaller distance to the prey and moved at speeds that were more synchronised with their co-predator. At high-range frequencies for fNIRS (0.1-0.2Hz), we found greater brain-to-brain synchrony in lateral and medial (frontopolar) PFC regions during hunting compared with chance levels. Together, these findings provide insights into what behaviours and brain dynamics associated with successful group hunting.

neuroscience↗

bioRxiv2022

Tuning the potency and therapeutic window of ImmTAC molecules by affinity modulation

T cell engaging bispecifics have great clinical potential for the treatment of cancer and infectious diseases. The binding affinity and kinetics of a bispecific molecule for both target and T cell CD3 have substantial effects on potency and specificity, but the rules governing these relationships are not fully understood. Using ImmTAC (Immune mobilizing monoclonal TCRs Against Cancer) molecules as a model, we explored the impact of altering affinity for target and CD3 on the potency and specificity of the re-directed T cell response. This class of bispecifics, exemplified by tebentafusp which has recently shown survival benefit in a randomized phase 3 clinical trial1, bind specific target peptides presented by human leukocyte antigen (HLA) on the cell surface via an affinity-enhanced T cell receptor and can redirect T cell activation with an anti-CD3 effector moiety. The data reveal that combining a strong affinity TCR with an intermediate affinity anti-CD3 results in optimal T cell activation, while strong affinity of both targeting and effector domains significantly reduces efficacy. Moreover, by optimising the affinity of both parts of the molecule, it is possible to improve the therapeutic window. These results could be effectively modelled based on kinetic proof-reading with limited signalling. This model explained the experimental observation that strong binding at both ends of the molecules leads to reduced activity, through very stable target-bispecific-effector complexes leading to CD3 entering a non-signalling dark-state. These findings have important implications for the design of anti-CD3 based bispecifics with optimal biophysical parameters for both activity and specificity. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=164 SRC="FIGDIR/small/511676v2_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@19ac262org.highwire.dtl.DTLVardef@14fb9fcorg.highwire.dtl.DTLVardef@13b5a52org.highwire.dtl.DTLVardef@1a6d096_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2021

Comparative meta-proteomic analysis for the identification of novel plasmodesmata proteins and regulatory cues.

A major route for cell-to-cell signaling is via cell wall-embedded pores termed plasmodesmata (PD) forming the symplasm. PD regulate many aspects of plant development and responses to the environment however, our understanding of what factors affect their structure and permeability is limited. In this paper, a meta-analysis is presented as a tool for the identification of conditions affecting PD transport and in silico generation of PD proteomes for species of interest. The custom-built pipeline searches the whole genome for protein structural features and conserved domains identified on experimental proteomes and use it to predict PD candidates in 22 compatible plant species. Using the in silico proteome and microarray analysis, interactions between PD genes and conditions affecting PD function are identified. High salinity and osmotic stress affect a significant number of PD candidate genes and we provide evidence that these conditions regulate symplasmic transport of GFP. Using the pipeline, the in silico PD proteome for Medicago truncatula was generated, as an example of a plant in which experimental data is not available. The identification of a candidate receptor like protein was experimentally validated in M. truncatula transgenic roots expressing fluorescently tagged protein fusion. Together the results highlight the power of our newly designed tool in the identification of new factors and proteins influencing PD in diverse plant species.

plant biology↗

bioRxiv2019

Plasma membrane associated Receptor Like Kinases relocalise to plasmodesmata in response to osmotic stress.

Plasmodesmata act as key elements in intercellular communication, coordinating processes related to plant growth, development and responses to environmental stresses. While many of the developmental, biotic and abiotic signals are primarily perceived at the plasma membrane (PM) by receptor proteins, plasmodesmata also cluster receptor-like activities and whether or not these two pathways interact is currently unknown.\n\nHere we show that specific PM-located Leucine-Rich-Repeat Receptor-Like-Kinases (LRR-RLKs), KIN7 and IMK2, which under optimal growth conditions are absented from plasmodesmata, rapidly relocate and cluster to the pores in response to osmotic stress. This process is remarkably fast, it is not a general feature of PM-associated proteins and is independent of sterol- and sphingolipid-membrane composition. Focusing on KIN7, previously reported to be involved in stress responses, we show that relocalisation upon mannitol depends on KIN7 phosphorylation. Loss-of-function mutation in KIN7 induces delay in lateral root (LR) development and the mutant is affected in the root response to mannitol stress. Callose-mediated plasmodesmata regulation is known to regulate LR development. We found that callose levels are reduced in kin7 mutant background with a root phenotype resembling ectopic expression of PdBG1, an enzyme that degrades callose at the pores. Both the LR and callose phenotypes can be complemented by expression of KIN7 -wild-type and -phosphomimic variants but not by KIN7 phosphodead mutant which fails to relocalise at plasmodesmata. Together the data indicate that re-organisation of RLKs to plasmodesmata is important for the regulation of callose and LR development as part of the plant response to osmotic stress.

plant biology↗