Department of Neurobiology; Budnik Lab; Graduate School of Biomedical Sciences, Neuroscience Program
Neuroscience and Neurobiology
Targeted membrane addition is a hallmark of many cellular functions. In the nervous system, modification of synaptic membrane size has a major impact on synaptic function. However, because of the complex shape of neurons and the need to target membrane addition to very small and polarized synaptic compartments, this process is poorly understood. Here, we show that Gtaxin (GTX), a Drosophila t-SNARE (target-soluble N-ethylmaleimide-sensitive factor attachment protein receptor), is required for expansion of postsynaptic membranes during new synapse formation. Mutations in gtx lead to drastic reductions in postsynaptic membrane surface, whereas gtx upregulation results in the formation of complex membrane structures at ectopic sites. Postsynaptic GTX activity depends on its direct interaction with Discs-Large (DLG), a multidomain scaffolding protein of the PSD-95 (postsynaptic density protein-95) family with key roles in cell polarity and formation of cellular junctions as well as synaptic protein anchoring and trafficking. We show that DLG selectively determines the postsynaptic distribution of GTX to type I, but not to type II or type III boutons on the same cell, thereby defining sites of membrane addition to this unique set of glutamatergic synapses. We provide a mechanistic explanation for selective targeted membrane expansion at specific synaptic junctions.
DOI of Published Version
J Neurosci. 2007 Jan 31;27(5):1033-44. Link to article on publisher's site
The Journal of neuroscience : the official journal of the Society for Neuroscience
Gorczyca, David; Ashley, James A.; Speese, Sean; Gherbesi, Norberto G.; Thomas, Ulrich; Gundelfinger, Eckart; Gramates, L. Sian; and Budnik, Vivian, "Postsynaptic membrane addition depends on the Discs-Large-interacting t-SNARE Gtaxin" (2007). GSBS Student Publications. 524.