Biology subjects

Subramanian, B. C.

Publications and source records attributed to Subramanian, B. C..

3 recordsLinked to original sources

bioRxiv2026

Spatially Distinct Myosin II Architectures Regulate Protrusion Dynamics and Directional Persistence during Immune Cell Migration

Directional persistence is essential for efficient immune cell migration in tissues, yet how cytoskeletal systems stabilize migration in complex three-dimensional environments remains unclear. Using intravital subcellular microscopy and quantitative analysis of membrane dynamics, we identify two spatially distinct architectures of non-muscle myosin II (NMII) that coordinate protrusion dynamics during neutrophil migration. In vivo and in collagen matrices, NMII assembles at the leading edge into lattice-like structures that are structurally and functionally distinct from rear contractile actomyosin bundles. Protrusion-resolved analyses reveal that directional persistence correlates strongly with protrusion lifetime and sustained NMII engagement, with rear NMII load showing the strongest association with protrusion persistence. Strikingly, directional migration is not determined by the abundance of favorable protrusions but by their temporal organization during migration. Pharmacological perturbations that redistribute NMII activity disrupt this temporal organization and alter migration trajectories. Together, these findings reveal that spatially distinct NMII architectures coordinate protrusion dynamics across time to stabilize directional migration in complex environments. HighlightsO_LIMigrating neutrophils assemble spatially distinct myosin II architectures at the leading edge and rear C_LIO_LIProtrusion dynamics and directional persistence are linked to sustained myosin II engagement C_LIO_LIDirectional migration emerges from the temporal organization of protrusion states rather than their abundance C_LI

cell biology↗

bioRxiv2022

Zyxin and non-muscle myosin are required for single fibroblast durotaxis, but Rho-kinase activity and the Arp2/3 complex are dispensable

Durotaxis, migration of cells directed by stiffness gradient, is critical in development and disease. To study the molecular determinants of single cell durotaxis, we developed an all-in-one photopolymerized hydrogel system containing areas of stiffness gradients with different slopes, along with uniform stiffness (soft and stiff) regions. We find that fibroblasts rely on non-muscle myosin II (NMII) activity and the LIM-domain protein zyxin for durotaxis on both steep and shallow stiffness gradients. Importantly, unlike haptotaxis, the Arp2/3 complex is dispensable for durotaxis on both stiffness gradients. Lack of Arp2/3 results in a filopodia-based durotactic migration that is equally efficient as that of lamellipodia-based durotactic migration. Finally, we reveal an essential role for the actin-bundler fascin in the formation and asymmetric distribution of filopodia during filopodia-based durotaxis in shallow, but not steep, stiffness gradient. Together, our all-in-one hydrogel system can serve as a platform to identify, discriminate, and characterize stiffness gradient specific molecular mechanisms that cells employ to efficiently durotax.

cell biology↗

bioRxiv2019

The LTB4-BLT1 signaling axis coordinates actomyosin dynamics and β-2 Integrin trafficking to drive intravascular neutrophil response to infection

The eicosanoid Leukotriene B4 (LTB4) relays chemotactic signals to direct neutrophil migration to inflamed sites through its receptor BLT1. However, the mechanisms by which the LTB4-BLT1 axis relays chemotactic signals during intravascular neutrophil response to inflammation remain unclear. Here, we report that LTB4 produced by neutrophils acts as an autocrine/paracrine signal to direct the vascular recruitment, arrest and extravasation of neutrophils in a sterile inflammation model in the mouse footpad. Using Intravital Subcellular Microscopy (ISMic), we reveal that LTB4 elicits sustained cell polarization and adhesion responses during neutrophil arrest in vivo. Specifically, LTB4 signaling coordinates the dynamic redistribution of non-muscle Myosin IIA (NMIIA) and {beta}2-integrin (Itgb2), which facilitate neutrophil arrest and extravasation. Notably, we also found that neutrophils shed extracellular vesicles (EVs) in the vascular lumen, and that inhibition of EV release blocks LTB4-mediated autocrine/paracrine signaling required for neutrophil arrest and extravasation. Overall, we uncover a novel complementary mechanism by which LTB4 relays extravasation signals in neutrophils during early inflammation response. SUMMARYNeutrophils arrest and extravasate from the blood vessels in response to infection and injury. Using intravital subcellular microscopy, Subramanian et al. identify a role for extracellular vesicles-based autocrine/paracrine LTB4-BLT1 signaling in promoting the re-arrangement of actomyosin cytoskeleton and {beta}2-integrin during neutrophil extravasation in live animals.

cell biology↗