Hemin inhibits internalization of transferrin by reticulocytes and promotes phosphorylation of the membrane transferrin receptor

Journal Article · Thu Aug 01 04:00:00 EDT 1985 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.82.15.5170· OSTI ID:6085399

Cox, T M; O'Donnell, M W; Aisen, P; London, I M

Addition of hemin to reticulocytes inhibits incorporation of iron from transferrin. Heme also regulates protein synthesis in immature erythroid cells through its effects on phosphorylation of the initiation factor eIF-2. The authors have examined its effects on endocytosis of iron-transferrin and phosphorylation of the transferrin receptor. Hemin reduced iron transport but increased cell-associated transferrin. During uptake of SVI-labeled transferrin in the steady state, the use of a washing technique to dissociate bound transferrin on the cell membrane showed that radioligand accumulated on the surface of hemin-treated cells. Receptor phosphorylation was investigated by immunoprecipitation of reticulocyte extracts after metabolic labeling with (TSP)P/sub i/. In the absence of ligand, phosphorylated receptor was chiefly localized on cell stroma. Exposure to transferrin increased cytosolic phosphorylated receptor from 15-30% to approximately 50% of the total, an effect overcome by hemin treatment. The findings suggest a possible relationship of phosphorylation to endocytosis of the transferrin receptor in reticulocytes.

• Research Organization: Massachusetts Institute of Technology, Cambridge
• OSTI ID: 6085399
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States) Vol. 82:15; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550301* -- Cytology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BLOOD FORMATION
BODY FLUIDS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ERYTHROCYTES
ERYTHROPOIESIS
EVEN-ODD NUCLEI
GLOBULINS
GLOBULINS-BETA
HEME
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INHIBITION
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
IRON 59
IRON ISOTOPES
ISOTOPES
LIGHT NUCLEI
MAMMALS
MATERIALS
MEMBRANE TRANSPORT
MEMBRANES
METALLOPROTEINS
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHAGOCYTOSIS
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PHOSPHORYLATION
PIGMENTS
PORPHYRINS
PROTEINS
RABBITS
RADIOISOTOPES
RECEPTORS
RETICULOCYTES
TRANSFERRIN
VERTEBRATES