title: APPL1 gates long-term potentiation through its plekstrin homology domain.
abstract: Hippocampal synaptic plasticity involves both membrane trafficking events and intracellular signaling, but how these are coordinated is far from clear. The endosomal transport of glutamate receptors in and out of the postsynaptic membrane responds to multiple signaling cascades triggered by synaptic activity. In this work, we have identified adaptor protein containing a plekstrin homology domain, phosphotyrosine-binding domain and leucine zipper motif 1 (APPL1) as a crucial element linking trafficking and signaling during synaptic plasticity. We show that APPL1 knockdown specifically impairs PI3K-dependent forms of synaptic plasticity, such as long-term potentiation (LTP) and metabotropic-glutamate-receptor-dependent long-term depression (mGluR-LTD). Indeed, we demonstrate that APPL1 is required for the activation of the phosphatidylinositol triphosphate (PIP3) pathway in response to LTP induction. This requirement can be bypassed by membrane localization of PI3K and is related to phosphoinositide binding. Interestingly, inhibitors of PDK1 (also known as PDPK1) and Akt have no effect on LTP expression. Therefore, we conclude that APPL1 gates PI3K activation at the plasma membrane upon LTP induction, which is then relayed by downstream PIP3 effectors that are different from PDK1 and Akt.
authors.affiliation: Centro de Biología Molecular 'Severo Ochoa', Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid 28049, Spain mfernandezmonreal@gmail.com jaesteban@cbm.csic.es.
authors.forename: Mónica
authors.identifier: 0000-0001-7278-448X
authors.initials: M
authors.lastname: Fernández-Monreal
authors.affiliation: Centro de Biología Molecular 'Severo Ochoa', Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid 28049, Spain.
authors.forename: Carla
authors.initials: C
authors.lastname: Sánchez-Castillo
authors.affiliation: Centro de Biología Molecular 'Severo Ochoa', Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid 28049, Spain mfernandezmonreal@gmail.com jaesteban@cbm.csic.es.
authors.forename: José A
authors.initials: JA
authors.lastname: Esteban
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D049229:Dendritic Spines / Q000378:metabolism; D004789:Enzyme Activation; D006624:Hippocampus / Q000166:cytology; D017774:Long-Term Potentiation; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000072417:Protein Domains; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D034741:RNA, Small Interfering / Q000378:metabolism; D017208:Rats, Wistar; D015398:Signal Transduction; D013569:Synapses / Q000378:metabolism; D009435:Synaptic Transmission
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D009419:Nerve Tissue Proteins; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D034741:RNA, Small Interfering; C515694:Appl1 protein, rat; C000631434:Pdk1 protein, rat
keywords: APPL1; PI3K; Synaptic plasticity; Trafficking