Modulation of Dopamine D₂Receptor Signaling by Actin-Binding Protein (ABP-280)

Abstract

Proteins that bind to G protein-coupled receptors have recently been identified as regulators of receptor anchoring and signaling. In this study, actin-binding protein 280 (ABP-280), a widely expressed cytoskeleton-associated protein that plays an important role in regulating cell morphology and motility, was found to associate with the third cytoplasmic loop of dopamine D(2) receptors. The specificity of this interaction was originally identified in a yeast two-hybrid screen and confirmed by protein binding. The functional significance of the D(2) receptor-ABP-280 association was evaluated in human melanoma cells lacking ABP-280. D(2) receptor agonists were less potent in inhibiting forskolin-stimulated cAMP production in these cells. Maximal inhibitory responses of D(2) receptor activation were also reduced. Further yeast two-hybrid experiments showed that ABP-280 association is critically dependent on the carboxyl domain of the D(2) receptor third cytoplasmic loop, where there is a potential serine phosphorylation site (S358). Serine 358 was replaced with aspartic acid to mimic the effects of receptor phosphorylation. This mutant (D(2)S358D) displayed compromised binding to ABP-280 and coupling to adenylate cyclase. PKC activation also generated D(2) receptor signaling attenuation, but only in ABP-containing cells, suggesting a PKC regulatory role in D(2)-ABP association. A mechanism for these results may be derived from a role of ABP-280 in the clustering of D(2) receptors, as determined by immunocytochemical analysis in ABP-deficient and replete cells. Our results suggest a new molecular mechanism of modulating D(2) receptor signaling by cytoskeletal protein interaction.

Dopaminergic signaling in dendritic spines

“…The actin binding protein filamin A (ABP-280), a cytoskeleton-associated protein involved in cell morphology and motility, interacts with the IL3 of D2 and D3 receptors [81]. These same regions also mediate the interaction of D2/D3 receptors with protein 4.1N, the neuronal form of the 4.1 family of cytoskeletal proteins implicated in linking the spectrin-actin cytoskeleton to the plasma membrane [80].…”

“…Besides short peptide sequences involved in G protein and arrestin binding, the remaining portions of these intracellular domains are presumably free to interact with other proteins. Using approaches such as co-immunoprecipitation and the yeast two-hybrid system, an increasing number of DRIPs are being identified [41][42][43]53,[68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83]. The confirmed DRIPs and their suggested functions are summarized in Table 1.…”

The Adenosine A2A Receptor Interacts with the Actin-binding Protein α-Actinin

“…Proper attachment of dopamine D 2 receptors to the actin cytoskeleton through the actin-binding protein filamin A has been found to affect cell-surface clustering of this receptor (20). To analyze the plasma membrane expression pattern of A 2A R as a function of its ability to bind ␣-actinin, immunofluorescence experiments with A 2A R-FLAG-and A 2A ⌬CTR-FLAGtransfected HEK-293 cells were performed.…”

“…Recent studies have identified filamin A, another actin-cross-linking protein similar to ␣-actinin, as an intracellular binding partner for other heptaspanning membrane receptors, viz. the dopamine D 2 and D 3 receptors (20,21), the calcium-sensing receptor (22), and metabotropic glutamate receptors (23). A role for these interactions in the proper membrane targeting and synaptic localization of all these receptors has been proposed.…”

Chronic morphine treatment up-regulates mu opioid receptor binding in cells lacking filamin A

“…Filamin A is known to bind to various membrane and signaling molecules, see reviews (Stossel et al, 2001;van der Flier and Sonnenberg, 2001)}. More recently different laboratories, including our own, demonstrated that filamin A associates with various GPCRs, such as the D2 and D3 dopamine receptors (Li et al, 2000;Lin et al, 2001), the calcium-sensing receptor (CaR) (Awata et al, 2001;Hjalm et al, 2001), the metabotropic glutamate receptor type 7 (Enz, 2002), alpha1-adrenergic receptors (Zhang et al, 2004), calcitonin receptor (Seck et al, 2003) and the mu opioid receptor (MOP) (Onoprishvili et al, 2003). In some cases, such as the calcium sensing receptor and the MOP, the binding of filamin A is to the carboxyl tail, while for other receptors, such as the D2 and D3 dopamine receptors, the binding is to the third cytoplasmic loop.…”