Transferrin is made and bound by photoreceptor cells.
Retinal pigment epithelial cells, which form one aspect of the blood-retinal barrier, control the access of blood-borne components such as diferric transferrin to the neural retina. It has recently been shown that RPE cells remove iron from diferric transferrin in a low pH compartment and subsequently release it in a low molecular weight form that can be chelated by apo-transferrin (Hunt and Davis: J. Cell Physiol. 152:102-110, 1992). It is now shown that photoreceptor cells can bind diferric transferrin to receptors on their inner segments. Moreover, polymerase chain reaction and in situ hybridization show that cells of the neural retina, particularly photoreceptors, make apo-transferrin.
Davis
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AA
Department of Microbiology and Immunology, University of South Carolina Medical School, Columbia 29208.
Hunt
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RC
D001483:Base Sequence; D004247:DNA / Q000235:genetics; D006801:Humans; D006863:Hydrogen-Ion Concentration; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D010786:Photoreceptor Cells / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D010857:Pigment Epithelium of Eye / Q000737:chemistry / Q000166:cytology / Q000648:ultrastructure; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D011990:Receptors, Transferrin / Q000032:analysis / Q000378:metabolism; D014168:Transferrin / Q000235:genetics / Q000378:metabolism*
D012333:RNA, Messenger; D011990:Receptors, Transferrin; D014168:Transferrin; D004247:DNA