Muscle-associated Drosophila adducin regulates larval neuromuscular junction development and the localization of Draper to the synapse

Adducin, the cross linker of actin and spectrin, has important regulatory roles in the remodeling of submembranous cytoskeleton during synaptic development. In Drosophila, Drosophila adducins, encoded by hu-li tai shao (hts), are localized to both pre-synaptic and post-synaptic larval neuromuscular junction (NMJ). In animals with muscle-specific knock-down of Hts, NMJs are underdeveloped, whereas overexpression of Hts in the muscle results in NMJ overgrowth. Draper, a transmembrane engulfment receptor, has also been shown to regulate larval NMJ development and may interact with Hts. In vivo, Draper colocalizes with Hts at the postsynaptic region. Moreover, in animals with muscle-specific knock-down of Hts, Draper is more tightly localized to the synapse, whereas overexpression of Hts causes delocalization of Draper immunoreactivity from the synapse. This delocalization of Draper induced by Hts highlights a new avenue by which Hts may be exerting its influence on NMJ development.