Focusing on motor behaviour, muscle mass, NMJ structure and survival, which are all profoundly affected in motor neuron disease, we show that disruption of either TBPH/TDP-43 or Caz/FUS enhance muscle defects but are able to suppress NMJ morphology deficits, both induced by Gemin3 loss-of-function. The gene discussed is TARDBP; the disease is motor neuron disorder.