title: Retinyl ester homeostasis in the adipose differentiation-related protein-deficient retina.
abstract: The retinal pigmented epithelium (RPE) plays an essential role in vision, including storing and converting retinyl esters of the visual chromophore, 11-cis-retinal. Retinyl ester storage structures (RESTs), specialized lipid droplets within the RPE, take up retinyl esters synthesized in the endoplasmic reticulum. Here we report studies of mice lacking exons 2 and 3 of the gene encoding adipose differentiation-related protein (Adfp), a structural component of RESTs. We found that dark adaptation was slower in Adfp(Delta2-3/Delta2-3) than in Adfp+/+ mice and that Adfp(Delta2-3/Delta2-3) mice had consistently delayed clearances of all-trans-retinal and all-trans-retinol from rod photoreceptor cells. Two-photon microscopy revealed aberrant trafficking of all-trans-retinyl esters in the RPE of Adfp(Delta2-3/Delta2-3) mice, a problem caused by abnormal maintenance of RESTs in the dark-adapted state. Retinyl ester accumulation was also reduced in Adfp(Delta2-3/Delta2-3) as compared with Adfp+/+ mice. These observations suggest that Adfp plays a unique role in vision by maintaining proper storage and trafficking of retinoids within the eye.
authors.affiliation: Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106, USA. yxi19@case.edu
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Imanishi
authors.forename: Wenyu
authors.initials: W
authors.lastname: Sun
authors.forename: Tadao
authors.initials: T
authors.lastname: Maeda
authors.forename: Akiko
authors.initials: A
authors.lastname: Maeda
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Palczewski
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000502:physiology; D003623:Dark Adaptation / Q000502:physiology*; D005091:Exons / Q000502:physiology; D006706:Homeostasis / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D000070780:Perilipin-2; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000378:metabolism*; D017948:Retinal Rod Photoreceptor Cells / Q000166:cytology / Q000378:metabolism*; D012172:Retinaldehyde / Q000235:genetics / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D000070780:Perilipin-2; C000602983:Plin2 protein, mouse; D012172:Retinaldehyde