title: FLRT proteins are endogenous latrophilin ligands and regulate excitatory synapse development.
abstract: Latrophilins (LPHNs) are a small family of G protein-coupled receptors known to mediate the massive synaptic exocytosis caused by the black widow spider venom α-latrotoxin, but their endogenous ligands and function remain unclear. Mutations in LPHN3 are strongly associated with attention deficit hyperactivity disorder, suggesting a role for latrophilins in human cognitive function. Using affinity chromatography and mass spectrometry, we identify the FLRT family of leucine-rich repeat transmembrane proteins as endogenous postsynaptic ligands for latrophilins. We demonstrate that the FLRT3 and LPHN3 ectodomains interact with high affinity in trans and that interference with this interaction using soluble recombinant LPHN3, LPHN3 shRNA, or FLRT3 shRNA reduces excitatory synapse density in cultured neurons. In addition, reducing FLRT3 levels with shRNA in vivo decreases afferent input strength and dendritic spine number in dentate granule cells. These observations indicate that LPHN3 and its ligand FLRT3 play an important role in glutamatergic synapse development.
authors.affiliation: Neurobiology Section, Division of Biology, University of California San Diego, La Jolla, CA 92093, USA.
authors.forename: Matthew L
authors.initials: ML
authors.lastname: O'Sullivan
authors.forename: Joris
authors.initials: J
authors.lastname: de Wit
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Savas
authors.forename: Davide
authors.initials: D
authors.lastname: Comoletti
authors.forename: Stefanie
authors.initials: S
authors.lastname: Otto-Hitt
authors.forename: John R
authors.initials: JR
authors.lastname: Yates
authors.forename: Anirvan
authors.initials: A
authors.lastname: Ghosh
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001921:Brain; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D002851:Chromatography, High Pressure Liquid; D018920:Coculture Techniques; D000076122:Disks Large Homolog 4 Protein; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D018274:Electroporation; D004622:Embryo, Mammalian; D019706:Excitatory Postsynaptic Potentials / Q000235:genetics / Q000502:physiology*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology; D018698:Glutamic Acid / Q000378:metabolism / Q000494:pharmacology; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D013058:Mass Spectrometry; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism* / Q000493:pharmacokinetics; D051379:Mice; D009154:Mutation / Q000235:genetics; D009474:Neurons / Q000166:cytology*; D018408:Patch-Clamp Techniques; D011247:Pregnancy; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D018000:Receptors, Peptide / Q000235:genetics / Q000378:metabolism*; D013347:Subcellular Fractions; D020349:Surface Plasmon Resonance; D013569:Synapses / Q000235:genetics / Q000502:physiology*; D016708:Synaptophysin / Q000378:metabolism; D014162:Transfection
chemical_list: C513284:ADGRL3 protein, human; C501444:DLG4 protein, human; D000076122:Disks Large Homolog 4 Protein; C404492:FLRT3 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D043562:Receptors, G-Protein-Coupled; D018000:Receptors, Peptide; D016708:Synaptophysin; D049452:Green Fluorescent Proteins; D018698:Glutamic Acid