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.

Ethanol and Naltrexone Have Distinct Effects on the Lateral Nano-organization of Mu and Kappa Opioid Receptors in the Plasma Membrane

“…Another possibility is the involvement of filamin A, an actinbinding protein that cross-links actin filaments into a dynamic three-dimensional structure and links them to numerous structurally and functionally diverse membrane proteins. About 20% of all GPCRs have a conserved filamin A binding motif, 89 and filamin A has been shown to bind to MOR. 89,90 However, NTX may circumstantially prevent MOR−filamin A interactions.…”

“…About 20% of all GPCRs have a conserved filamin A binding motif, 89 and filamin A has been shown to bind to MOR. 89,90 However, NTX may circumstantially prevent MOR−filamin A interactions. 91,92 Thus, NTX may have a dual effect on MOR function, its canonical action as an antagonist of MORmediated signaling and the potential to affect MOR−filamin A complexes.…”

Angiotensin II Signal Transduction: An Update on Mechanisms of Physiology and Pathophysiology

“…The list of AT 1 R interacting proteins has now been expanded to include filamin A, a cross-linking signal transducer (1055), tubulin (1258), Coatomer subunit ␤ (␤-COP) (1275), and GABA receptor-associated protein (GABARAP) (182). Filamin A and tubulin are associated with the cellular cytoskeleton, and the tubulin/AT 1 R interaction contributes to AT 1 R trafficking to the cell surface (1055,1258). ␤-COP is a component of Coat Protein I (COPI) transport vesicles involved in the transport between different Golgi stacks and transport from the Golgi to the ER.…”

AT1 receptor signaling pathways in the cardiovascular system

“…Tubulin directly binds to the AT1 receptor, regulating AT1 receptor trafficking from the ER to the cell surface (130). AT1 receptor also directly binds to filamin A, an actin cross-linking protein, with agonist activation of the AT1 receptor promoting filamin phosphorylation, suggestive of a direct role of AT1 receptor in actin remodeling mediated by filamin (131). β-COP (Coatomer subunit β), a component of Coat Protein I (COPI) transport vesicles involved in the transport between different Golgi stacks and transport from the Golgi to the ER, interacts with AT1 receptor on Lys308 and regulates AT1 receptor export trafficking to the cell surface (132).…”