Design principles of Cdr2 node patterns in fission yeast cells

Biological pattern formation is essential for organizing cellular components. Fission yeast cells use spatial patterning to regulate mitotic signaling and cytokinetic ring positioning. The Cdr2 kinase forms membrane-bound nodes that are positioned in the cell center. These nodes are influenced by the inhibitor Pom1, which is enriched at cell tips. Understanding how these nodes are positioned is important for cell cycle control. Prior research has shown that Pom1 and Cdr2 interact to regulate node localization. However, the specific roles of nuclear positioning and cortical anchoring remain unclear. This gap motivated a combined experimental and computational approach. The study aimed to clarify how node positioning is achieved in different cellular contexts.

The study aimed to investigate how Cdr2 nodes are positioned in fission yeast cells. The researchers focused on the interplay between Pom1, Cdr2, and cellular structures like the nucleus and cortex. They sought to determine whether node positioning depends on nuclear presence or cortical anchoring. The study tested whether tip inhibition alone could position nodes. The researchers also examined how node patterns change in multinucleated cells. They used simulations and experiments to compare model predictions with observed patterns. The goal was to understand the design principles of node positioning. This work could clarify how spatial control is achieved in cytokinesis.

The researchers used a combination of experiments and simulations to study node positioning. They observed Cdr2 localization in cells with altered cortical anchoring. They tracked nucleocytoplasmic shuttling of Cdr2 when anchoring was reduced. Particle-based simulations were developed to model node positioning. These simulations included factors like tip inhibition and nuclear positioning. The model predictions were tested in cells with modified positioning mechanisms. The experiments included anucleate and multinucleated cells. Localization patterns were analyzed after perturbing each mechanism. The results were compared to the simulation outputs to validate the model.

Cdr2 nodes were found to accumulate near the nucleus in fission yeast cells. Cdr2 undergoes nucleocytoplasmic shuttling when cortical anchoring is reduced. Simulations based on tip inhibition and cortical anchoring predicted node positioning. Experiments confirmed that tip inhibition and anchoring alone position nodes without the nucleus. In multinucleated cells, the nucleus and Pom1 influenced unexpected node patterns. The simulations matched observed patterns in anucleate cells. Node positioning was not strictly dependent on nuclear presence. The findings suggest that multiple factors contribute to node positioning.

The study showed that tip inhibition and cortical anchoring are sufficient for node positioning in the absence of the nucleus. The nucleus and Pom1 contribute to node patterns in multinucleated cells. These findings suggest that multiple mechanisms control node positioning. The results support the idea that node positioning is robust to nuclear absence. The simulations accurately predicted experimental outcomes. The findings have implications for spatial control of cytokinesis. The study highlights the importance of Pom1 in node regulation. The results may inform future studies on pattern formation in other systems.