title: Drosophila Vision Depends on Carcinine Uptake by an Organic Cation Transporter.
abstract: Recycling of neurotransmitters is essential for sustained neuronal signaling, yet recycling pathways for various transmitters, including histamine, remain poorly understood. In the first visual ganglion (lamina) of Drosophila, photoreceptor-released histamine is taken up into perisynaptic glia, converted to carcinine, and delivered back to the photoreceptor for histamine regeneration. Here, we identify an organic cation transporter, CarT (carcinine transporter), that transports carcinine into photoreceptors during histamine recycling. CarT mediated in vitro uptake of carcinine. Deletion of the CarT gene caused an accumulation of carcinine in laminar glia accompanied by a reduction in histamine, resulting in abolished photoreceptor signal transmission and blindness in behavioral assays. These defects were rescued by expression of CarT cDNA in photoreceptors, and they were reproduced by photoreceptor-specific CarT knockdown. Our findings suggest a common role for the conserved family of CarT-like transporters in maintaining histamine homeostasis in both mammalian and fly brains.
authors.affiliation: Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Ratna
authors.initials: R
authors.lastname: Chaturvedi
authors.affiliation: Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Luan
authors.affiliation: Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Peiyi
authors.initials: P
authors.lastname: Guo
authors.affiliation: Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA. Electronic address: hong-sheng.li@umassmed.edu.
authors.forename: Hong-Sheng
authors.initials: HS
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002336:Carnosine / Q000031:analogs & derivatives* / Q000378:metabolism; D027682:Cation Transport Proteins / Q000502:physiology*; D002460:Cell Line; D029721:Drosophila Proteins / Q000502:physiology*; D004331:Drosophila melanogaster / Q000502:physiology*; D017956:Photoreceptor Cells, Invertebrate / Q000502:physiology; D009435:Synaptic Transmission; D014785:Vision, Ocular
chemical_list: D027682:Cation Transport Proteins; D029721:Drosophila Proteins; D002336:Carnosine; C015055:carcinine
keywords: histamine; membrane transporter; neurotransmitter recycling; vision