Open AccessALS2 regulates endosomal trafficking, postsynaptic development, and neuronal survival
Author(s) -
Joohyung Kim,
Sungdae Kim,
Minyeop Nahm,
Tsai-Ning Li,
Hsin-Chieh Lin,
Yeongjin David Kim,
Jihye Lee,
Chi-Kuang Yao,
Seungbok Lee
Publication year - 2021
Publication title -
the journal of cell biology/the journal of cell biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.414
H-Index - 380
eISSN - 1540-8140
pISSN - 0021-9525
DOI - 10.1083/jcb.202007112
Subject(s) - biology , endosome , neurodegeneration , microbiology and biotechnology , guanine nucleotide exchange factor , postsynaptic potential , small gtpase , rab , phenotype , gtpase , signal transduction , genetics , gene , receptor , medicine , disease , pathology , intracellular
Mutations in the human ALS2 gene cause recessive juvenile-onset amyotrophic lateral sclerosis and related motor neuron diseases. Although the ALS2 protein has been identified as a guanine-nucleotide exchange factor for the small GTPase Rab5, its physiological roles remain largely unknown. Here, we demonstrate that the Drosophila homologue of ALS2 (dALS2) promotes postsynaptic development by activating the Frizzled nuclear import (FNI) pathway. dALS2 loss causes structural defects in the postsynaptic subsynaptic reticulum (SSR), recapitulating the phenotypes observed in FNI pathway mutants. Consistently, these developmental phenotypes are rescued by postsynaptic expression of the signaling-competent C-terminal fragment of Drosophila Frizzled-2 (dFz2). We further demonstrate that dALS2 directs early to late endosome trafficking and that the dFz2 C terminus is cleaved in late endosomes. Finally, dALS2 loss causes age-dependent progressive defects resembling ALS, including locomotor impairment and brain neurodegeneration, independently of the FNI pathway. These findings establish novel regulatory roles for dALS2 in endosomal trafficking, synaptic development, and neuronal survival.