Text Box: After completion of the myopodia clustering behavior, stabilized myopodia dynamically interact with the corresponding innervating motoneuron axon to form a synaptic connection... Text Box: Synaptogenesis Text Box: We have been unable to detect DLG::GFP in individual myopodia (data not shown). However, soon after the myopodia forms its cluster we are able to detect DLG::GFP in the cluster... Text Box: DLG enters myopodia cluster Text Box: During development of neuromuscular synapses in both invertebrates and vertebrates, the muscle cells extend highly animated myopodia (postsynaptic filopodia) and dynamically interact with the innervating motoneuron axons... Text Box: Myopodia appears Text Box: Starting approximately 40 minutes prior to neuromuscular synaptogenesis, myopodia start to aggregate in a myopodia cluster. Myopodia clusters eventually leading to the formation of a new sub-cellular compartment where signaling and other events take place... Text Box: Myopodia clustering Text Box: We have observed DLG entering the myopodia cluster soon after its formation Text Box: DLG and neuronal interaction Text Box: Some time after the sub-cellular space created by the myopodia cluster disappears, we observe smaller, secondary processes from a maturing synapse that cause DLG to accumulate underneath them. Text Box: DLG and the maturing synapse

Myopodia Behavior Study

This part of my research is designed to understand any underlying behavioral pattern of myopodia.  Myopodia is the term we assigned to the actin-based post-synaptic filopodia structures that appear in every muscle cell (see “myopodia appears” for additional details).

Previously, our lab demonstrated that myopodial behavior is tightly correlated with synaptic target recognition events.  At higher resolutions, we have also shown that myopodial clustering is followed by lamellopodia-like membrane protrusion, suggesting the involvement of cell adhesion molecules.  This cluster formation is immediately followed by the recruitment of cytoskeletal and subsynaptic components, such as discs large.

Studying the underlying myopodial behavioral pattern allows for assessing the role they play within the dynamic cellular context in which synaptogenesis proceeds.  Also to pinpoint any behavior difference when interacting with non-innervating axons and with its corresponding innervating partner.

Based on current data and models we propose that intimate filopodia clustering, coupled to rapid remodeling of cytoskeletal and other sub-cellular components, is essential at the site of contact between synaptic partners for reliable synaptogenesis to proceed in vivo.
Text Box: Myopodia (muscle filopodia) appear to be involved in other events. We have been able to observe myopodia crossing the midline and reaching over to myopodia coming from the opposite hemisegment. We have also seen myopodia at the muscle insertion sites... Text Box: Other myopodia interactions