Secreted amyloid-β precursor protein functions as a GABA<sub>B</sub>R1a ligand to modulate synaptic transmission.

Rice, Heather C; de Malmazet, Daniel; Schreurs, An; Frere, Samuel; Van Molle, Inge; Volkov, Alexander N; Creemers, Eline; Vertkin, Irena et al. · Science · 2019

basic_science · Level V

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Abstract

Amyloid-β precursor protein (APP) is central to the pathogenesis of Alzheimer's disease, yet its physiological function remains unresolved. Accumulating evidence suggests that APP has a synaptic function mediated by an unidentified receptor for secreted APP (sAPP). Here we show that the sAPP extension domain directly bound the sushi 1 domain specific to the γ-aminobutyric acid type B receptor subunit 1a (GABA<sub>B</sub>R1a). sAPP-GABA<sub>B</sub>R1a binding suppressed synaptic transmission and enhanced short-term facilitation in mouse hippocampal synapses via inhibition of synaptic vesicle release. A 17-amino acid peptide corresponding to the GABA<sub>B</sub>R1a binding region within APP suppressed in vivo spontaneous neuronal activity in the hippocampus of anesthetized Thy1-GCaMP6s mice. Our findings identify GABA<sub>B</sub>R1a as a synaptic receptor for sAPP and reveal a physiological role for sAPP in regulating GABA<sub>B</sub>R1a function to modulate synaptic transmission.

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