記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Frontiers Media SA  

The growth cone, a motile structure located at the tip of growing axons, senses extracellular guidance cues and translates them into directional forces that drive axon outgrowth and guidance. Axon guidance directed by chemical cues on the extracellular adhesive substrate is termed haptotaxis. Recent studies reported that netrin-1 on the substrate functions as a haptotactic axon guidance cue. However, the mechanism mediating netrin-1–induced axonal haptotaxis remains unclear. Here, we demonstrate that substrate-bound netrin-1 induces axonal haptotaxis by facilitating physical interactions between the netrin-1 receptor, DCC, and the adhesive substrates. DCC serves as an adhesion receptor for netrin-1. The clutch-linker molecule shootin1a interacted with DCC, linking it to actin filament retrograde flow at the growth cone. Speckle imaging analyses showed that DCC underwent either grip (stop) or retrograde slip on the adhesive substrate. The grip state was more prevalent on netrin-1–coated substrate compared to the control substrate polylysine, thereby transmitting larger traction force on the netrin-1–coated substrate. Furthermore, disruption of the linkage between actin filament retrograde flow and DCC by shootin1 knockout impaired netrin-1–induced axonal haptotaxis. These results suggest that the directional force for netrin-1–induced haptotaxis is exerted on the substrates through the adhesion-clutch between DCC and netrin-1 which occurs asymmetrically within the growth cone.

DOI： 10.3389/fnmol.2024.1307755

PubMed

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：eLife Sciences Publications, Ltd  

Axon outgrowth is promoted by the mechanical coupling between F-actin and adhesive substrates via clutch and adhesion molecules in an axonal growth cone. In this study, we utilized a femtosecond laser-induced impulse to break the coupling between the growth cone and the substrate, enabling us to evaluate the strength of the binding between the growth cone and a laminin on the substrate, and also determine the contribution of adhesion strength to axon outgrowth and traction force for the outgrowth. We found that the adhesion strength of axonal L1 cell adhesion molecule (L1CAM)-laminin binding increased with the laminin density on the substrate. In addition, fluorescent speckle microscopy revealed that the retrograde flow of F-actin in the growth cone was dependent on the laminin density such that the flow speed reduced with increasing L1CAM-laminin binding. However, axon outgrowth and the traction force did not increase monotonically with increased L1CAM-laminin binding but rather exhibited biphasic behavior, in which the outgrowth was suppressed by excessive L1CAM-laminin binding. Our quantitative evaluations suggest that the biphasic outgrowth is regulated by the balance between traction force and adhesion strength. These results imply that adhesion modulation is key to the regulation of axon guidance.

DOI： 10.7554/elife.93700.1

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オープンデータURL： https://elifesciences.org/reviewed-preprints/93700v2

DOI： 10.1101/2023.12.03.569828

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

Axon pathfinding is an essential step in neuronal network formation. Shootin1a is a clutch-linker molecule that is mechanically involved in axon outgrowth and guidance. It was previously shown that concentration gradients of axon guidance molecule netrin-1 in the extracellular environment elicit asymmetrically localized Pak1 kinase-mediated phosphorylation of shootin1a within axonal growth cones, which is higher on the netrin-1 source side. This asymmetric phosphorylation promotes shootin1a-mediated local actin-adhesion coupling within growth cones, thereby generating directional forces for turning the growth cone toward the netrin-1 source. However, how the spatial differences in netrin-1 concentration are transduced into the asymmetrically localized signaling within growth cones remains unclear. Moreover, the protein phosphatases that dephosphorylate shootin1a remain unidentified. Here, we report that protein phosphatase-1 (PP1) dephosphorylates shootin1a in growth cones. We found that PP1 overexpression abolished the netrin-1-induced asymmetric localization of phosphorylated shootin1a as well as axon turning. In addition, we show PP1 inhibition reversed the asymmetrically localized shootin1a phosphorylation within growth cones under netrin-1 gradient, thereby changing the netrin-1-induced growth cone turning from attraction to repulsion. These data indicate that PP1-mediated shootin1a dephosphorylation plays a key role in organizing asymmetrically localized phosphorylated shootin1a within growth cones, which regulates netrin-1-induced axon guidance.

DOI： 10.1016/j.jbc.2023.104687

PubMed

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.celrep.2021.109130

オープンデータURL： https://www.sciencedirect.com/science/article/pii/S2211124721004691?via%3Dihub

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.bpj.2021.08.009

オープンデータURL： https://www.sciencedirect.com/science/article/pii/S000634952100655X?via%3Dihub

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.bioconjchem.0c00239

オープンデータURL： https://pubs.acs.org/bcches/article/31/6/1611/588480/An-Artificial-Amphiphilic-Peptide-Promotes

DOI： 10.1038/s42003-019-0486-3

オープンデータURL： https://www.nature.com/articles/s42003-019-0486-3

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7554/eLife.34593

オープンデータURL： https://elifesciences.org/articles/34593

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1073/pnas.1711667115

オープンデータURL： https://www.pnas.org/doi/full/10.1073/pnas.1711667115

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1083/jcb.201505011

オープンデータURL： https://rupress.org/jcb/article/210/4/663/38262/Shootin1-cortactin-interaction-mediates-signal