Actin-dependent endocytosis at the leading edge of the growth cone

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K06459
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 46010:Neuroscience-general-related
• Research Institution: Niigata University
• Principal Investigator: Nozumi Motohiro 新潟大学, 医歯学系, 講師 (00420323)
• Co-Investigator(Kenkyū-buntansha): 伊藤 泰行 新潟大学, 医歯学系, 助教 (70710573)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 成長円錐 / アクチン / 超解像顕微鏡

Outline of Final Research Achievements

Growth cones are essential for proper neural circuit formation and axon regeneration. At the leading edge of the growth cone, the plasma membrane is pushed by the elongation of the actin cytoskeleton, which generates the driving force for axon outgrowth. In this study, we found non-adhesive filopodia extending vertically from the surface of the growth cones by three-dimensional observations using super-resolution microscopy, 3D-SIM. The filopodia showed lipid raft-dependent accumulation of neuropilin-1, an axon guidance receptor, and repeated elongation and retraction within a minute. The growth cone could actively recruit receptors toward the extracellular space through the filopodia elongation, suggesting that they efficiently capture soluble ligands.

Free Research Field

細胞生物学

Academic Significance and Societal Importance of the Research Achievements

走化性に特化した成長円錐は非神経細胞に比べると非常に小さく、これまで正確な３次元画像の取得が難しかった。本研究ではxy平面だけでなく、z軸方向でも共焦点レーザー顕微鏡の約２倍の分解能をもつ構造化照明法による超解像顕微鏡（3D-SIM）を使い、成長円錐表面の微小突起が走化性に重要な役割を果たしている可能性を初めて示した。非神経細胞では同様の構造がいくつか報告されており、細胞構造の精密な３次元可視化によって新たなメカニズムの解明につながることが期待できる。