title: G protein-coupled receptors directly bind filamin A with high affinity and promote filamin phosphorylation.
abstract: Although interaction of a few G protein-coupled receptors (GPCRs) with Filamin A, a key actin cross-linking and biomechanical signal transducer protein, has been observed, a comprehensive structure-function analysis of this interaction is lacking. Through a systematic sequence-based analysis, we found that a conserved filamin binding motif is present in the cytoplasmic domains of >20% of the 824 GPCRs encoded in the human genome. Direct high-affinity interaction of filamin binding motif peptides of select GPCRs with the Ig domain of Filamin A was confirmed by nuclear magnetic resonance spectroscopy and isothermal titration calorimetric experiments. Engagement of the filamin binding motif with the Filamin A Ig domain induced the phosphorylation of filamin by protein kinase A in vitro. In transfected cells, agonist activation as well as constitutive activation of representative GPCRs dramatically elicited recruitment and phosphorylation of cellular Filamin A, a phenomenon long known to be crucial for regulating the structure and dynamics of the cytoskeleton. Our data suggest a molecular mechanism for direct GPCR-cytoskeleton coupling via filamin. Until now, GPCR signaling to the cytoskeleton was predominantly thought to be indirect, through canonical G protein-mediated signaling cascades involving GTPases, adenylyl cyclases, phospholipases, ion channels, and protein kinases. We propose that the GPCR-induced filamin phosphorylation pathway is a conserved, novel biochemical signaling paradigm.
authors.affiliation: Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic , Cleveland, Ohio 44195, United States.
authors.forename: Kalyan C
authors.initials: KC
authors.lastname: Tirupula
authors.affiliation: Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic , Cleveland, Ohio 44195, United States.
authors.forename: Sujay S
authors.initials: SS
authors.lastname: Ithychanda
authors.affiliation: Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic , Cleveland, Ohio 44195, United States.
authors.forename: Maradumane L
authors.initials: ML
authors.lastname: Mohan
authors.affiliation: Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic , Cleveland, Ohio 44195, United States.
authors.forename: Sathyamangla V
authors.initials: SV
authors.lastname: Naga Prasad
authors.affiliation: Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic , Cleveland, Ohio 44195, United States.
authors.forename: Jun
authors.initials: J
authors.lastname: Qin
authors.affiliation: Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic , Cleveland, Ohio 44195, United States.
authors.forename: Sadashiva S
authors.initials: SS
authors.lastname: Karnik
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D064448:Filamins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D064448:Filamins; D043562:Receptors, G-Protein-Coupled; D017868:Cyclic AMP-Dependent Protein Kinases