Open Close
Chaplot, K., Pimpale, L., Ramalingam, B., Deivasigamani, S., Kamat, S.S., Ratnaparkhi, G.S. (2019). SOD1 activity threshold and TOR signalling modulate VAP(P58S) aggregation via reactive oxygen species-induced proteasomal degradation in a Drosophila model of amyotrophic lateral sclerosis.  Dis. Model Mech. 12(2): dmm033803.
FlyBase ID
Publication Type
Research paper

Familial amyotrophic lateral sclerosis (ALS) is an incurable, late-onset motor neuron disease, linked strongly to various causative genetic loci. ALS8 codes for a missense mutation, P56S, in VAMP-associated protein B (VAPB) that causes the protein to misfold and form cellular aggregates. Uncovering genes and mechanisms that affect aggregation dynamics would greatly help increase our understanding of the disease and lead to potential therapeutics. We developed a quantitative high-throughput Drosophila S2R+ cell-based kinetic assay coupled with fluorescent microscopy to score for genes involved in the modulation of aggregates of the fly orthologue, VAP(P58S), fused with GFP. A targeted RNA interference screen against 900 genes identified 150 hits that modify aggregation, including the ALS loci Sod1 and TDP43 (also known as TBPH), as well as genes belonging to the mTOR pathway. Further, a system to measure the extent of VAP(P58S) aggregation in the Drosophila larval brain was developed in order to validate the hits from the cell-based screen. In the larval brain, we find that reduction of SOD1 levels or decreased mTOR signalling reduces aggregation, presumably by increasing the levels of cellular reactive oxygen species (ROS). The mechanism of aggregate clearance is, primarily, proteasomal degradation, which appears to be triggered by an increase in ROS. We have thus uncovered an interesting interplay between SOD1, ROS and mTOR signalling that regulates the dynamics of VAP aggregation. Mechanistic processes underlying such cellular regulatory networks will lead to better understanding of the initiation and progression of ALS.This article has an associated First Person interview with the first author of the paper.

PubMed ID
PubMed Central ID
PMC6398501 (PMC) (EuropePMC)
Associated Information
Associated Files
Other Information
Secondary IDs
    Language of Publication
    Additional Languages of Abstract
    Parent Publication
    Publication Type
    Dis. Model Mech.
    Disease models & mechanisms
    1754-8403 1754-8411
    Data From Reference
    Alleles (18)
    Genes (184)
    Human Disease Models (2)
    Cell Lines (1)
    Natural transposons (1)
    Insertions (2)
    Experimental Tools (3)
    Transgenic Constructs (16)