Moesin helps to restrain synaptic growth at the Drosophila neuromuscular junction.
The precise role of actin and actin-binding proteins in synaptic development is unclear. In Drosophila, overexpression of a dominant-negative NSF2 construct perturbs filamentous actin, which is associated with overgrowth of the NMJ, while co-expression of moesin, which encodes an actin binding protein, suppresses this overgrowth phenotype. These data suggest that Moesin may play a role in synaptic development at the Drosophila NMJ. To further investigate this possibility, we examined the influence of loss-of-function moesin alleles on the NSF2-induced overgrowth phenotype. We found that flies carrying P-element insertions that reduce moesin expression enhanced the NMJ overgrowth phenotype, indicating a role for Moesin in normal NMJ morphology. In addition to the NMJ overgrowth phenotype, expression of dominant-negative NSF2 is known to reduce the frequency of miniature excitatory junctional potentials and the amplitude of excitatory junctional potentials. We found that moesin coexpression did not restore the physiology of the mutant NSF2 phenotype. Together, our results demonstrate a role for moesin in regulating synaptic growth in the Drosophila NMJ and suggest that the effect of dominant-negative NSF2 on NMJ morphology and physiology may have different underlying molecular origins.
Seabrooke
Sara
S
Department of Biology, University of Toronto, Mississauga, Ontario, Canada L5L 1C6.
Stewart
Bryan A
BA
D000199:Actins / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D030801:Animals, Genetically Modified; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004625:Embryo, Nonmammalian; D005786:Gene Expression Regulation / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D016014:Linear Models; D008564:Membrane Potentials / Q000235:genetics / Q000528:radiation effects; D008840:Microfilament Proteins / Q000502:physiology*; D009132:Muscles / Q000166:cytology; D009154:Mutation / Q000502:physiology; D052066:N-Ethylmaleimide-Sensitive Proteins / Q000502:physiology*; D009469:Neuromuscular Junction / Q000502:physiology*
D000199:Actins; D029721:Drosophila Proteins; D008840:Microfilament Proteins; C498738:Nsf2 protein, Drosophila; C071058:moesin; D049452:Green Fluorescent Proteins; D052066:N-Ethylmaleimide-Sensitive Proteins