Genetic detects in acetylcholine signalling promote protein degradation inmuscle cells of Caenorhabditis elegans

A myosin-lacZ fusion, expressed in 103 muscle cells of Caenorhabditis elega ns, reports on how proteolysis in muscle is controlled by neural and intram uscular signals. Upon acute starvation, the fusion protein is degraded in t he posterior 63 cells of the body-wall muscle, but remains stable in 32 ant erior body-wall muscles and 8 vulval muscle cells. This distinction correla tes with differences in the innervation of these cells. Reporter protein in the head and vulval muscles becomes labile upon genetic 'denervation' in m utants that have blocks in pre-synaptic synthesis or release of acetylcholi ne (ACh) or post-synaptic reception at nicotinic ACh receptors (nAChR), whe reas protein in all 103 muscles is stabilized by the nicotinic agonist leva misole in the absence of ACh production. Levamisole does nor stabilize musc le protein in nAChR mutants that are behaviorally resistant to levamisole, Neural inputs thus exert negative control over the proteolytic process in m uscle by stimulating muscle nicotinic ACh receptors.