Nak透過胞飲作用促進樹突生長

Abstract

During development, dendrites arborize in a field several hundred folds of their soma size, a process regulated by intrinsic transcription programs and cell adhesion molecule (CAM)-mediated dendrodendritic interaction. However, underlying cellular machineries that govern distal higher-order dendrite extension remain largely unknown. Here, I show that Nak, a clathrin adaptor-associated kinase, promotes higher-order dendrite growth through endocytosis. In nak mutants, the number and length of higher-order dendrites are reduced, which are phenocopied by compromising clathrin-mediated internalization. Nak genetically interacts with genes involved in endocytosis, colocalizes with clathrin puncta and is required for localization of clathrin puncta in distal dendrites. Furthermore, these clathrin structures preferentially localize to branching points and dendritic tips that are undergoing active growth. I present evidence to show that the Drosophila L1-CAM homolog Neuroglian is a relevant cargo of Nak-dependent internalization, suggesting that localized clathrin-mediated endocytosis of CAMs facilitates the extension of nearby higher-order dendrites.