SorCS1-mediated Sorting of Neurexin in Dendrites Maintains Presynaptic Function
Luís F. Ribeiro, Ben Verpoort, Julie Nys, Kristel M. Vennekens, Keimpe D. Wierda, and Joris de Wit
Received Date 11th March 2019
The pre- and postsynaptic membranes comprising the synaptic junction differ in protein composition. The mechanisms that maintain the polarized distribution of synaptic membrane proteins are poorly understood. The sorting receptor SorCS1 is a critical traffickingregulator of neuronal receptors, includingneurexin (Nrxn), a presynaptic adhesion molecule essential for synaptic transmission. We find that SorCS1 controls a balance between axonal and dendritic Nrxn1α surface levels. Newly synthesized Nrxn1α traffics to the somatodendritic surface, followed by endocytosis. SorCS1 interacts with the Rab11 effector protein Rab11FIP5/Rip11 to facilitate the transition of internalized Nrxn1α from early to recycling endosomes and bias Nrxn1α surface polarization toward the axon. In the absence of SorCS1, Nrxn1α accumulates in early endosomes and mis-polarizes to the dendritic surface, impairing presynaptic function. The axonal/dendritic balance of Nrxn1α surface distribution is activity-dependent, indicating that SorCS1-mediated sorting in somatodendritic endosomes dynamically controls Nrxn1α axonal surface polarization required for proper presynaptic function.
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This is an abstract of a preprint hosted on an independent third party site. It has not been peer reviewed but is currently under consideration at Nature Communications.