Elizabeth’s BioBlog

        The identification and characterization of key components in neuromuscular synaptogenesis has been the object of study in past decades. The field has been progressively advancing as processes such as axon path-finding and synaptic targeting are being better understood. However, researchers in post-synaptic dynamics and trafficking have yet much to discover, specifically in the study of protein transport to the post synaptic density (PSD). The PSD is a sub-cellular specialization at neuronal synapses thought to organize the postsynaptic signaling complexes required for accumulation of scaffold proteins such as PSD95/Dlg. During  the formation of the neuromuscular junction in Drosophila melanogaster, the PSD is assembled at the tip actin-filled filopodia called myopodia that are extended by the post-synaptic cell (muscle). Non-muscle myosin, a motor protein, mediates the intracellular transport of Dlg and may also be responsible for transporting various cell adhesion molecules (CAMs) throughout the myopodia and into the PSD. In this study we aim to understand the role motor proteins and CAMs play in muscle innervation. By identifying the specific myosin responsible for intra-myopodial trafficking and the spatiotemporal pattern for CAM transport, we can start to dissect the sequence of events that ultimately leads to a functional synapse. This new knowledge can lead to both clinical and industrial applications in different fields,such as bioengineering. To accomplish this we used fluorescent confocal imaging together with both in vitro and in vivo immunohistochemical staining using genetically encoded green fluorescent protein (GFP) bioprobes. This approach allows us to track and characterize the individual function of both myosin and CAMs in neuromuscular synaptogenesis. Also, by a developmental time course we can determine the stage and specific timepoint where the immunostaining becomes apparent.  Surprisingly, while looking for myosin in myopodia during a developmental time course we came upon myosin in extended filopodia of the developing foregut epithelium. A concentrated amount of myosin in the extended filopodia suggests an additional function in the closure of the tube-like structure. Additional studies are necessary to understand the role of myosin in this developmental context in Drosophila development. Furthermore, we are still in the process of identifying the particular myosin and CAMs involved in key processes in neuromuscular synaptogenesis. This project is sponsored by BioMinds.