Biology subjects

Matsubayashi, H. T.

Publications and source records attributed to Matsubayashi, H. T..

4 recordsLinked to original sources

bioRxiv2024

Light-guided actin polymerization drives directed motility in protocells

Motility is a hallmark of lifes dynamic processes, enabling cells to actively chase prey, repair wounds, and shape organs. Recreating these intricate behaviors using well-defined molecules remains a major challenge at the intersection of biology, physics, and molecular engineering. Although the polymerization force of the actin cytoskeleton is characterized as a primary driver of cell motility, building a minimal platform to test this process in protocellular systems has proven elusive. The difficulty lies in the daunting task of distilling key components from motile cells and integrating them into model membranes in a physiologically relevant manner. To address this, we developed a method to optically control actin polymerization with high spatiotemporal precision within cell-mimetic lipid vesicles known as giant unilamellar vesicles (GUVs). Within these active protocells, the reorganization of actin networks triggered outward membrane extensions as well as the unidirectional movement of GUVs at speeds of up to 0.43 {micro}m/min, within the range of adherent mammalian cells. Notably, our findings reveal the requirements of both branched and linear actin networks for efficient membrane protrusions. This approach offers a powerful platform for unraveling the intricacies of cell migration, designing synthetic cells with active morphodynamics, and advancing bioengineering applications, such as self-propelled delivery systems and autonomous tissue-like materials.

synthetic biology↗

bioRxiv2023

Synthetic control of actin polymerization and symmetry breaking in activeprotocells

Non-linear biomolecular interactions on the membranes drive membrane remodeling that underlies fundamental biological processes including chemotaxis, cytokinesis, and endocytosis. The multitude of biomolecules, the redundancy in their interactions, and the importance of spatiotemporal context in membrane organization hampers understanding the physical principles governing membrane mechanics. A minimal, in vitro system that models the functional interactions between molecular signaling and membrane remodeling, while remaining faithful to cellular physiology and geometry is powerful yet remains unachieved. Here, inspired by the biophysical processes underpinning chemotaxis, we reconstituted externally-controlled actin polymerization inside giant unilamellar vesicles, guiding self-organization on the membrane. We show that applying undirected external chemical inputs to this system results in directed actin polymerization and membrane deformation that are uncorrelated with upstream biochemical cues, indicating symmetry breaking. A biophysical model of the dynamics and mechanics of both actin polymerization and membrane shape suggests that inhomogeneous distributions of actin generate membrane shape deformations in a non-linear fashion, a prediction consistent with experimental measurements and subsequent local perturbations. The active protocellular system demonstrates the interplay between actin dynamics and membrane shape in a symmetry breaking context that is relevant to chemotaxis and a suite of other biological processes.

synthetic biology↗

bioRxiv2023

Non-catalytic role of phosphoinositide 3-kinase in mesenchymal cell migration through non-canonical induction of p85beta/AP-2-mediated endocytosis

Class IA phosphoinositide 3-kinase (PI3K) galvanizes fundamental cellular processes such as migration, proliferation, and differentiation. To enable multifaceted roles, the catalytic subunit p110 utilizes a multi- domain, regulatory subunit p85 through its inter SH2 domain (iSH2). In cell migration, their product PI(3,4,5)P3 generates locomotive activity. While non-catalytic roles are also implicated, underlying mechanisms and its relationship to PI(3,4,5)P3 signaling remain elusive. Here, we report that a disordered region of iSH2 contains previously uncharacterized AP-2 binding motifs which can trigger clathrin and dynamin-mediated endocytosis independent of PI3K catalytic activity. The AP-2 binding motif mutants of p85 aberrantly accumulate at focal adhesions and upregulate both velocity and persistency in fibroblast migration. We thus propose the dual functionality of PI3K in the control of cell motility, catalytic and non- catalytic, arising distinctly from juxtaposed regions within iSH2.

cell biology↗

bioRxiv2022

Dynamin forms liquid-like condensates at synapses to support ultrafast endocytosis

Endocytosis at synapses is accelerated by the pre-accumulation of Dynamin 1xA at the endocytic zone by Syndapin 1. However, it is unclear how these proteins support the ultrafast kinetics of endocytosis. Here we report that these proteins phase separate at the presynaptic endocytic zone where ultrafast endocytosis takes place. Specifically, the proline-rich motif of Dynamin 1xA interacts with the Src-Homology 3 domain of Syndapin 1 and forms liquid-like condensates. Single-particle tracking of Dynamin 1xA molecules at synapses shows that their diffusion slows down substantially when they are in the condensates, indicating the presence of molecular crowding and intermolecular interaction. When Dynamin 1xA is mutated to disrupt its interaction with Syndapin 1 the condensates do not form. Thus, the liquid-like assembly of these endocytic proteins provides a catalytic platform for ultrafast endocytosis.

neuroscience↗