Biology subjects

Suzuki, K. G. N.

Publications and source records attributed to Suzuki, K. G. N..

2 recordsLinked to original sources

bioRxiv2020

High-speed single-molecule imaging reveals signal transduction by induced transbilayer raft phases

Using single-molecule imaging with enhanced time resolutions down to 5 ms, we found that CD59-cluster rafts and GM1-cluster rafts stably induced in the outer leaflet of the plasma membrane (PM), which triggered the activation of Lyn, H-Ras, and ERK, continually recruited Lyn and H-Ras right beneath them in the inner leaflet, with dwell lifetimes of <0.1 s. The detection was possible due to the enhanced time resolutions employed here. The recruitment depended on the PM cholesterol and saturated alkyl chains of Lyn and H-Ras, whereas it was blocked by the non-raftophilic transmembrane protein moiety and unsaturated alkyl chains linked to the inner-leaflet molecules. Since GM1-cluster rafts recruited Lyn and H-Ras as efficiently as CD59-cluster rafts, and the protein moieties of Lyn and H-Ras were not required for the recruitment, we conclude that the transbilayer raft phases induced by the outer-leaflet stabilized rafts recruit lipid-anchored signaling molecules by lateral raft-lipid interactions, and thus serve as a key signal transduction platform. SummaryHigh-speed single-molecule imaging indicated that CD59-cluster rafts and GM1-cluster rafts stably induced in the plasma membrane outer leaflet generated nano-scale transbilayer raft phases, which continually and transiently recruited Lyn and H-Ras in the inner leaflet by cooperative raft-lipid interactions.

cell biology↗

bioRxiv2019

Dynamic actin-mediated nano-scale clustering of CD44 regulates its meso-scale organization at the plasma membrane

Transmembrane adhesion receptors at the cell surface, such as CD44, are often equipped with modules to interact with the extracellular-matrix(ECM) and the intra-cellular cytoskeletal machinery. CD44 has been recently shown to compartmentalize the membrane into domains by acting as membrane pickets, facilitating the function of signaling receptors. While spatial organization and diffusion studies of membrane proteins are usually conducted separately, here we combine observations of organization and diffusion by using high spatio-temporal resolution imaging on living cells to reveal a hierarchical organization of CD44. CD44 is present in a meso-scale meshwork pattern where it exhibits enhanced confinement and is enriched in nano-clusters of CD44 along its boundaries. This nanoclustering is orchestrated by the underlying cortical actin dynamics. Interaction with actin is mediated by specific segments of the intracellular-domain(ICD). This influences the organization of the protein at the nano-scale, generating a selective requirement for formin over Arp2/3-based actin-nucleation machinery. The extracellular-domain(ECD) and its interaction with elements of ECM do not influence the meso-scale organization, but may serve to reposition the meshwork with respect to the ECM. Taken together, our results capture the hierarchical nature of CD44 organization at the cell surface, with active cytoskeleton-templated nano-clusters localized to a meso-scale meshwork pattern.

cell biology↗