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📰 "Protein phosphorylation networks in Baylisascaris procyonis revealed by phosphoproteomic analysis"
doi.org/doi:10.1186/s13071-025
pubmed.ncbi.nlm.nih.gov/407221
#Cytoskeletal #Dynamics

BioMed CentralProtein phosphorylation networks in Baylisascaris procyonis revealed by phosphoproteomic analysis - Parasites & VectorsBackground Baylisascaris procyonis is an intestinal ascarid worm that parasitizes in raccoons and causes fatal neural, visceral, and ocular larva migrans in humans. Phosphorylated proteins and protein kinases have been studied as vaccine and drug target candidates against parasitic infections. However, no data are available on protein phosphorylation in the raccoon roundworm. Methods In this study, the entire proteome of adult B. procyonis was enzymatically digested. Then, phosphopeptides were enriched using immobilized metal affinity chromatography (IMAC) and analyzed by liquid chromatography-mass spectrometry (LC-MS/MS). Results Our phosphoproteome analysis displayed 854 unique phosphorylation sites mapped to 450 proteins in B. procyonis (3308 phosphopeptides total). The annotated phosphoproteins were associated with various biological processes, including cytoskeletal remodeling, supramolecular complex assembly, and developmental regulation. The phosphopeptide functional enrichment revealed that B. procyonis phosphoproteins were mostly involved in the cytoskeleton cellular compartment, protein binding molecular function, and multiple biological processes, including regulating supramolecular fiber and cytoskeleton organization and assembling cellular protein-containing complexes and organelles. The significantly enriched pathways of phosphoproteins included the insulin signaling pathway, tight junction, endocytosis, longevity-regulating, glycolysis/gluconeogenesis, and apelin signaling pathways. Domain analysis revealed that the Src homology 3 domain was significantly enriched. Conclusions This study presents the first phosphoproteomic landscape of B. procyonis, elucidating phosphorylation-mediated regulation of cytoskeletal dynamics, host interaction pathways, and metabolic adaptations. The identified 450 phosphoproteins and enriched functional domains establish a foundation for targeting conserved mechanisms critical to B. procyonis survival. Graphical Abstract

📰 "Evolution of robust cell differentiation under epigenetic feedback"
arxiv.org/abs/2503.20651 #Physics.Bio-Ph #Dynamics #Nlin.Ao #Cell

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arXiv.orgEvolution of robust cell differentiation under epigenetic feedbackIn multi-cellular organisms, cells differentiate into multiple types as they divide. States of these cell types, as well as their numbers, are known to be robust to external perturbations; as conceptualized by Waddington's epigenetic landscape where cells embed themselves in valleys corresponding to final cell types. How is such robustness achieved by developmental dynamics and evolution? To address this question, we consider a model of cells with gene expression dynamics and epigenetic feedback, governed by a gene regulation network. By evolving the network to achieve more cell types, we identified three major differentiation processes exhibiting different properties regarding their variance, attractors, stability, and robustness. The first of these, type A, exhibits chaos and long-lived oscillatory dynamics that slowly transition until reaching a steady state. The second, type B, follows a channeled annealing process where the epigenetic changes in combination with noise shift the cells towards varying final cell states that increase the stability. Lastly, type C exhibits a quenching process where cell fate is quickly decided by falling into pre-existing fixed points while cell trajectories are separated through periodic attractors or saddle points. We find types A and B to correspond well with Waddington's landscape while being robust. Finally, the dynamics of type B demonstrate a differentiation process that uses a directed shifting of fixed points, visualized through the dimensional reduction of gene-expression states. Correspondence with the experimental data of gene expression variance through differentiation is also discussed.

📰 "Self-organization drives symmetry-breaking, scaling, and critical growth transitions in stem cell-derived organoids"
arxiv.org/abs/2507.18887 #Physics.Bio-Ph #Dynamics #Q-Bio.To #Cell

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arXiv.orgSelf-organization drives symmetry-breaking, scaling, and critical growth transitions in stem cell-derived organoidsThe emergence of spatial patterns and organized growth is a hallmark of developing tissues. While symmetry-breaking and scaling laws govern these processes, how cells coordinate spatial patterning with size regulation remains unclear. Here, we combine quantitative imaging, a Turing activator-repressor model with self-organized reactive boundaries, and in vitro models of early mouse development to study mesodermal pattern formation in two-dimensional (2D) gastruloids. We show that colony size dictates symmetry: small colonies (radius approximately 100 micrometers) spontaneously break symmetry, while larger ones remain centro-symmetric, consistent with size-dependent positional information and model predictions. The mesodermal domain area scales robustly with colony size following a power law, independent of cell density, indicating that cells sense and respond to gastruloid size. Time-lapse imaging reveals a biphasic growth law: an early power-law expansion followed by exponential arrest, marking a dynamical phase transition. These dynamics, conserved across sizes, reflect features of criticality seen in physical systems, where self-organization, scaling, and boundary feedback converge. Our findings uncover a minimal mechanism for size-dependent pattern formation and growth control. This framework enables quantitative investigation of symmetry-breaking and scaling in self-organizing tissues, offering insights into the physical principles underlying multicellular organization.

📰 "Competing chemical gradients change chemotactic dynamics and cell distribution"
arxiv.org/abs/2507.19341 #Physics.Bio-Ph #Mechanical #Dynamics #Q-Bio.Cb #Cell

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arXiv.orgCompeting chemical gradients change chemotactic dynamics and cell distributionCells are constantly exposed to diverse stimuli-chemical, mechanical, or electrical-that guide their movement. In physiological conditions, these signals often overlap, as seen during infections, where neutrophils and dendritic cells navigate through multiple chemotactic fields. How cells integrate and prioritize competing signals remains unclear. For instance, in the presence of opposing chemoattractant gradients, how do cells decide which direction to go? When should local signals dominate distant ones? A key factor in these processes is the precision with which cells sense each gradient, which depends non-monotonically on concentrations. Here, we study how gradient sensing accuracy shapes cell navigation in the presence of two distinct chemoattractant sources. We model cells as active random walkers that sense local gradients and combine these estimates to reorient their movement. Our results show that cells sensing multiple gradients can display a range of chemotactic behaviors, including anisotropic spatial patterns and varying degrees of confinement, depending on gradient shape and source location. The model also predicts cases where cells exhibit multistep navigation across sources or a hierarchical response toward one source, driven by disparities in their sensitivity to each chemoattractant. These findings highlight the role of gradient sensing in shaping spatial organization and navigation strategies in multi-field chemotaxis.