Construction of Dendrites and Synapses
Neurons are the fundamental unit that makes up our brain. They are born of different types with distinct morphology, which is mostly accounted for by the dendritic trees. One fascinating question to answer is how neurons grow such exuberant dendrites once they are born. We have been using Drosophila dendritic arborization (da) neurons as the model system to study dendrite development. There are four types of da neurons (classes I-IV) with class IV da (c4da) neurons being most complex in terms of morphology. We envision that cellular machineries such as endocytosis and exocytosis are highly active during dendrite elaboration. Mainly by fluorescence imaging techniques and fly genetics, we investigate how various cellular processes such as Golgi dynamics, protein glycosylation and cell-cell interaction may contribute to dendrite arborization.
Neurons are largely of no use without activation and connection. The sites that neurons are connected to each other or to their targets such as muscles are called synapses. Chemical synapses utilize neurotransmitters to relay the electrical signals from neurons to neurons. Through exocytosis, presynapses release neurotransmitters, which are received by postsynaptic receptors. The synapses at the Drosophila neuromuscular junction (NMJ) have been a model system to study how they are built during development. In this direction, we have been actively studying how protein ubiquitination and proteasomal degradation contribute to the building of postsynaptic structures such as membrane folding and receptor clustering. Interestingly, the NMJ also displays structural plasticity in response to synaptic activity. We are dissecting the underlying mechanism to understand how synaptic plasticity is manifested and modulated.