title: Astrocyte-to-neuron communication through integrin-engaged Thy-1/CBP/Csk/Src complex triggers neurite retraction via the RhoA/ROCK pathway.
abstract: Two key proteins for cellular communication between astrocytes and neurons are αvβ3 integrin and the receptor Thy-1. Binding of these molecules in the same (cis) or on adjacent (trans) cellular membranes induces Thy-1 clustering, triggering actin cytoskeleton remodeling. Molecular events that could explain how the Thy-1-αvβ3 integrin interaction signals have only been studied separately in different cell types, and the detailed transcellular communication and signal transduction pathways involved in neuronal cytoskeleton remodeling remain unresolved. Using biochemical and genetic approaches, single-molecule tracking, and high-resolution nanoscopy, we provide evidence that upon binding to αvβ3 integrin, Thy-1 mobility decreased while Thy-1 nanocluster size increased. This occurred concomitantly with inactivation and exclusion of the non-receptor tyrosine kinase Src from the Thy-1/C-terminal Src kinase (Csk)-binding protein (CBP)/Csk complex. The Src inactivation decreased the p190Rho GTPase activating protein phosphorylation, promoting RhoA activation, cofilin, and myosin light chain II phosphorylation and, consequently, neurite shortening. Finally, silencing the adaptor CBP demonstrated that this protein was a key transducer in the Thy-1 signaling cascade. In conclusion, these data support the hypothesis that the Thy-1-CBP-Csk-Src-RhoA-ROCK axis transmitted signals from astrocytic integrin-engaged Thy-1 (trans) to the neuronal actin cytoskeleton. Importantly, the β3 integrin in neurons (cis) was not found to be crucial for neurite shortening. This is the first study to detail the signaling pathway triggered by αvβ3, the endogenous Thy-1 ligand, highlighting the role of membrane-bound integrins as trans acting ligands in astrocyte-neuron communication.
authors.affiliation: Laboratorio de Comunicaciones Celulares, Centro de Estudios Moleculares de la Célula, Advanced Center for Chronic Disease (ACCDiS), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Chile; Biomedical Neuroscience Institute (BNI), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Chile.
authors.forename: H
authors.initials: H
authors.lastname: Maldonado
authors.affiliation: Laboratorio de Comunicaciones Celulares, Centro de Estudios Moleculares de la Célula, Advanced Center for Chronic Disease (ACCDiS), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Chile.
authors.forename: C
authors.initials: C
authors.lastname: Calderon
authors.affiliation: Laboratorio de Comunicaciones Celulares, Centro de Estudios Moleculares de la Célula, Advanced Center for Chronic Disease (ACCDiS), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Chile; Biomedical Neuroscience Institute (BNI), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Chile.
authors.forename: F
authors.initials: F
authors.lastname: Burgos-Bravo
authors.affiliation: Leibniz Institute for Neurobiology, Magdeburg, Germany.
authors.forename: O
authors.initials: O
authors.lastname: Kobler
authors.affiliation: Leibniz Institute for Neurobiology, Magdeburg, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Zuschratter
authors.affiliation: Biomedical Neuroscience Institute (BNI), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Chile; Laboratory of Scientific Image Analysis (SCIAN), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Chile.
authors.forename: O
authors.initials: O
authors.lastname: Ramirez
authors.affiliation: Biomedical Neuroscience Institute (BNI), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Chile; Laboratory of Scientific Image Analysis (SCIAN), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Chile.
authors.forename: S
authors.initials: S
authors.lastname: Härtel
authors.affiliation: Department of Biochemistry, University of Lausanne, 1066 Epalinges, Switzerland.
authors.forename: P
authors.initials: P
authors.lastname: Schneider
authors.affiliation: Laboratorio de Comunicaciones Celulares, Centro de Estudios Moleculares de la Célula, Advanced Center for Chronic Disease (ACCDiS), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Chile.
authors.forename: A F G
authors.initials: AF
authors.lastname: Quest
authors.affiliation: Leibniz Institute for Neurobiology, Magdeburg, Germany. Electronic address: rherrera@lin-magdeburg.de.
authors.forename: R
authors.initials: R
authors.lastname: Herrera-Molina
authors.affiliation: Laboratorio de Comunicaciones Celulares, Centro de Estudios Moleculares de la Célula, Advanced Center for Chronic Disease (ACCDiS), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Chile; Biomedical Neuroscience Institute (BNI), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Chile. Electronic address: lleyton@med.uchile.cl.
authors.forename: L
authors.initials: L
authors.lastname: Leyton
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000166:cytology*; D002450:Cell Communication; D002478:Cells, Cultured; D039302:Integrin alphaVbeta3 / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D016501:Neurites; D009474:Neurons / Q000166:cytology*; D010750:Phosphoproteins / Q000378:metabolism*; D051381:Rats; D018800:Thy-1 Antigens / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism*
chemical_list: D039302:Integrin alphaVbeta3; D008565:Membrane Proteins; C408142:Pag1 protein, rat; D010750:Phosphoproteins; D018800:Thy-1 Antigens; D019061:src-Family Kinases; D020742:rhoA GTP-Binding Protein
keywords: Cell adhesion molecules; GPI-anchored proteins; Interaction in trans; RhoA; STED microscopy; αvβ3 integrin