title: Reciprocal Phosphorylation and Palmitoylation Control Dopamine Transporter Kinetics.
abstract: The dopamine transporter is a neuronal protein that drives the presynaptic reuptake of dopamine (DA) and is the major determinant of transmitter availability in the brain. Dopamine transporter function is regulated by protein kinase C (PKC) and other signaling pathways through mechanisms that are complex and poorly understood. Here we investigate the role of Ser-7 phosphorylation and Cys-580 palmitoylation in mediating steady-state transport kinetics and PKC-stimulated transport down-regulation. Using both mutational and pharmacological approaches, we demonstrate that these post-translational modifications are reciprocally regulated, leading to transporter populations that display high phosphorylation-low palmitoylation or low phosphorylation-high palmitoylation. The balance between the modifications dictates transport capacity, as conditions that promote high phosphorylation or low palmitoylation reduce transport Vmax and enhance PKC-stimulated down-regulation, whereas conditions that promote low phosphorylation or high palmitoylation increase transport Vmax and suppress PKC-stimulated down-regulation. Transitions between these functional states occur when endocytosis is blocked or undetectable, indicating that the modifications kinetically regulate the velocity of surface transporters. These findings reveal a novel mechanism for control of DA reuptake that may represent a point of dysregulation in DA imbalance disorders.
authors.affiliation: From the Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9061.
authors.forename: Amy E
authors.initials: AE
authors.lastname: Moritz
authors.affiliation: From the Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9061.
authors.forename: Danielle E
authors.initials: DE
authors.lastname: Rastedt
authors.affiliation: From the Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9061.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Stanislowski
authors.affiliation: From the Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9061.
authors.forename: Madhur
authors.initials: M
authors.lastname: Shetty
authors.affiliation: From the Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9061.
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Smith
authors.affiliation: From the Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9061 roxanne.vaughan@med.und.edu.
authors.forename: Roxanne A
authors.initials: RA
authors.lastname: Vaughan
authors.affiliation: From the Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9061 james.d.foster@med.und.edu.
authors.forename: James D
authors.initials: JD
authors.lastname: Foster
mesh_terms: D002460:Cell Line; D004298:Dopamine / Q000235:genetics / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation / Q000502:physiology*; D004705:Endocytosis / Q000502:physiology*; D006801:Humans; D007700:Kinetics; D054878:Lipoylation / Q000502:physiology*; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism*
chemical_list: D050483:Dopamine Plasma Membrane Transport Proteins; D011493:Protein Kinase C; D004298:Dopamine
keywords: DHHC; acyl protein transferases; post-translational modification (PTM); protein acylation; protein kinase C (PKC); protein palmitoylation; protein phosphorylation