Dominant negative mutants of filamin A block cell surface expression of the D2 dopamine receptor.
Protein interaction screens have revealed an interaction between the D2 dopamine receptor and the actin cross-linking protein filamin A. However, the physiological significance of this interaction has not been explained. To better understand the role of filamin A in D2 receptor-mediated signaling, we examined the effect of disrupting filamin A/D2 receptor interaction. Overexpression of a truncated form of filamin A (repeat units 18-19 containing the D2, but not the actin, binding domain) caused a marked reduction in both the number and half-life of cell surface D2 receptors. These results suggest that disruption of the linkage between D2 receptors and the actin cytoskeleton destabilizes plasma membrane-associated D2 receptors. Several missense mutations within repeat unit 19 of filamin A were identified that abrogate filamin A/D2 receptor interaction. Introduction of mutant and wild-type filamin A into filamin A-deficient M2 cells demonstrated that wild-type filamin A, but not the filamin A-binding mutants, was able to promote cell-surface expression of D2 receptors. Together, these studies provide evidence that filamin A/D2 receptor interaction is required for the proper targeting or stabilization of D2 dopamine receptors at the plasma membrane.
Lin
Ridwan
R
Neuroscience Graduate Program, Penn State College of Medicine, Hershey, Pa., USA.
Canfield
Victor
V
Levenson
Robert
R
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002478:Cells, Cultured; D003285:Contractile Proteins / Q000494:pharmacology / Q000502:physiology*; D004347:Drug Interactions; D064448:Filamins; D008840:Microfilament Proteins / Q000494:pharmacology / Q000502:physiology*; D017448:Receptors, Dopamine D2 / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*
D003285:Contractile Proteins; D064448:Filamins; D008840:Microfilament Proteins; D017448:Receptors, Dopamine D2