Endocytosis of synaptic ADAM10 in neuronal plasticity and Alzheimer’s disease
Elena Marcello, … , Fabrizio Gardoni, Monica Di Luca
Elena Marcello, … , Fabrizio Gardoni, Monica Di Luca
Published May 8, 2013
Citation Information: J Clin Invest. 2013;123(6):2523-2538. https://doi.org/10.1172/JCI65401.
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Research Article Neuroscience

Endocytosis of synaptic ADAM10 in neuronal plasticity and Alzheimer’s disease

Abstract

A disintegrin and metalloproteinase 10 (ADAM10), a disintegrin and metalloproteinase that resides in the postsynaptic densities (PSDs) of excitatory synapses, has previously been shown to limit β-amyloid peptide (Aβ) formation in Alzheimer’s disease (AD). ADAM10 also plays a critical role in regulating functional membrane proteins at the synapse. Using human hippocampal homogenates, we found that ADAM10 removal from the plasma membrane was mediated by clathrin-dependent endocytosis. Additionally, we identified the clathrin adaptor AP2 as an interacting partner of a previously uncharacterized atypical binding motif in the ADAM10 C-terminal domain. This domain was required for ADAM10 endocytosis and modulation of its plasma membrane levels. We found that the ADAM10/AP2 association was increased in the hippocampi of AD patients compared with healthy controls. Long-term potentiation (LTP) in hippocampal neuronal cultures induced ADAM10 endocytosis through AP2 association and decreased surface ADAM10 levels and activity. Conversely, long-term depression (LTD) promoted ADAM10 synaptic membrane insertion and stimulated its activity. ADAM10 interaction with the synapse-associated protein-97 (SAP97) was necessary for LTD-induced ADAM10 trafficking and required for LTD maintenance and LTD-induced changes in spine morphogenesis. These data identify and characterize a mechanism controlling ADAM10 localization and activity at excitatory synapses that is relevant to AD pathogenesis.

Authors

Elena Marcello, Claudia Saraceno, Stefano Musardo, Hugo Vara, Alerie Guzman de la Fuente, Silvia Pelucchi, Daniele Di Marino, Barbara Borroni, Anna Tramontano, Isabel Pérez-Otaño, Alessandro Padovani, Maurizio Giustetto, Fabrizio Gardoni, Monica Di Luca

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Figure 6

LTD promotes ADAM10 insertion into the membranes, whereas LTP reduces ADAM10 membrane levels.

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LTD promotes ADAM10 insertion into the membranes, whereas LTP reduces AD...
(A) Immunoblot of ADAM10, GluR1-P845, GluR1, and actin from control and cLTD/cLTP-treated hippocampal cultures either exposed or not exposed to the crosslinker BS3. cLTD leads to a significant decrease in ADAM10 intracellular pool, which reflects an augment in ADAM10 surface expression. cLTP significantly increases ADAM10 intracellular pool because cLTP results in a decrease in ADAM10 membrane localization. As expected, cLTD induction reduces and cLTP increases the Ser-845 phosphorylation of GluR1. (B) Quantification of the ADAM10/Actin OD ratio of BS3-treated neurons of experiments in A (*P < 0.05 cLTD versus C, n = 7, cLTP versus C, n = 3). (C) After either cLTD or cLTP induction, hippocampal cultures were biotinylated and the extracts were precipitated with neutravidin. To avoid saturation of band signal in order to carry out precise quantitative analyses, samples of extracts (Tot) and neutravidin-precipitated samples (Pp) were loaded such that each lane represents a percentage of the total material per plate. Representative immunoblot of ADAM10 and GluR1 from control and treated cultures. (D) ADAM10 OD in Pp samples (surface) was measured and normalized to ADAM10 OD in tot samples (total) to calculate the surface/total ratio. Quantification of the surface/total ratio of experiments in C (*P < 0.05 cLTD versus C, n = 5, cLTP versus C, n = 6).