title: RalA employs GRK2 and β-arrestins for the filamin A-mediated regulation of trafficking and signaling of dopamine D2 and D3 receptor.
abstract: Filamin A (FLNA) is known to act as platform for the signaling and intracellular trafficking of various GPCRs including dopamine D2 and D3 receptors (D2R, D3R). To understand molecular mechanisms involved in the FLNA-mediated regulation of D2R and D3R, comparative studies were conducted on the signaling and intracellular trafficking of the D2R and D3R in FLNA-knockdown cells, with a specific focus on the roles of the proteins that interact with FLNA and the D2R and D3R. Lowering the level of cellular FLNA caused an elevation in RalA activity and resulted in selective interference with the normal intracellular trafficking and signaling of the D2R and D3R, through GRK2 and β-arrestins, respectively. Knockdown of FLNA or coexpression of active RalA interfered with the recycling of the internalized D2R and resulted in the development of receptor tolerance. Active RalA was found to interact with GRK2 to sequester it from D2R. Knockdown of FLNA or coexpression of active RalA prevented D3R from coupling with G protein. The selective involvement of GRK2- and β-arrestins in the RalA-mediated cellular processes of the D2R and D3R was achieved via their different modes of interactions with the receptor and their distinct functional roles in receptor regulation. Our results show that FLNA is a multi-functional protein that acts as a platform on which D2R and D3R can interact with various proteins, through which selective regulation of these receptors occurs in combination with GRK2 and β-arrestins.
authors.affiliation: Department of Pharmacology, College of Pharmacy, Drug Development Research Institute, Chonnam National University, Gwang-Ju 500-757, Republic of Korea.
authors.forename: Mei
authors.initials: M
authors.lastname: Zheng
authors.affiliation: Department of Pharmacology, College of Pharmacy, Drug Development Research Institute, Chonnam National University, Gwang-Ju 500-757, Republic of Korea.
authors.forename: Xiaohan
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Pharmacology, College of Pharmacy, Drug Development Research Institute, Chonnam National University, Gwang-Ju 500-757, Republic of Korea.
authors.forename: NingNing
authors.initials: N
authors.lastname: Sun
authors.affiliation: Department of Pharmacology, College of Pharmacy, Drug Development Research Institute, Chonnam National University, Gwang-Ju 500-757, Republic of Korea.
authors.forename: Chengchun
authors.initials: C
authors.lastname: Min
authors.affiliation: Department of Pharmacology, College of Pharmacy, Drug Development Research Institute, Chonnam National University, Gwang-Ju 500-757, Republic of Korea.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Pharmacology, College of Pharmacy, Drug Development Research Institute, Chonnam National University, Gwang-Ju 500-757, Republic of Korea. Electronic address: kmkim@jnu.ac.kr.
authors.forename: Kyeong-Man
authors.initials: KM
authors.lastname: Kim
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D000242:Cyclic AMP / Q000096:biosynthesis; D018491:Dopamine Agonists / Q000494:pharmacology; D064448:Filamins / Q000502:physiology*; D054769:G-Protein-Coupled Receptor Kinase 2 / Q000502:physiology*; D017930:Genes, Reporter; D057809:HEK293 Cells; D006801:Humans; D020935:MAP Kinase Signaling System / Q000502:physiology; D021381:Protein Transport / Q000502:physiology; D017448:Receptors, Dopamine D2 / Q000187:drug effects / Q000378:metabolism*; D050637:Receptors, Dopamine D3 / Q000187:drug effects / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D000071559:beta-Arrestin 1 / Q000502:physiology*; D000071560:beta-Arrestin 2 / Q000502:physiology*; D020725:ral GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: C581293:DRD2 protein, human; C493593:DRD3 protein, human; D018491:Dopamine Agonists; D064448:Filamins; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D011994:Recombinant Proteins; D000071559:beta-Arrestin 1; D000071560:beta-Arrestin 2; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; C496567:GRK2 protein, human; D054769:G-Protein-Coupled Receptor Kinase 2; C492198:RALA protein, human; D020725:ral GTP-Binding Proteins
keywords: Dopamine D2 receptor; Dopamine D3 receptor; Filamin A; GRK2; RalA; β-arrestin