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Internalisation and recycling of the granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) receptor on a murine myelomonocytic leukemia
Author(s) -
Walker Francesca,
Burgess Antony W.
Publication year - 1987
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041300211
Subject(s) - receptor , transferrin receptor , cell surface receptor , granulocyte macrophage colony stimulating factor , ligand (biochemistry) , biology , colony stimulating factor , biochemistry , chemistry , microbiology and biotechnology , in vitro , haematopoiesis , stem cell
Radioiodinated granulocyte‐macrophage colony‐stimulating factor ( 125 I‐GM‐CSF) binds to specific receptors (molecular weight approximately 50,000 daltons) on the murine myeiomonocytic leukemia, WEHI‐38D + . At 4°C 125 I‐GM‐CSF remains on the surface of the cells and can be eluted by washing the cells with acidified isotonic buffer. When the cells are warmed to 37°C, the 125 I‐GM‐CSF is internalized rapidly (t1/2: 7 min). The internalisation appears to be entirely receptor mediated and is independent of energy sources inhibited by sodium azide. This GM‐CSF‐mediated internalisation is not due to a general increase in the turnover of cell surface molecules as the specific binding of 25 I‐transferrin is not affected by incubation of WEHI‐3BD + cells with GM‐CSF. The initial 125 I released when the cells are warmed to 37°C appears to be intact 125 I‐GM‐CSF; however, after 2 h 80% of the 125 I released was not precipitable with trichloroacetic acid and presumably represented degraded 125 I‐GM‐CSF. Ammonium chloride or monensin reduced the release of 125 I‐GM‐CSF from the cells, suggesting that the receptor‐bound ligand was processed through the lysosomes. A cor siderable proportion of the internalised GM‐CSF receptors were recycled to the surface and were available for ligand binding. Synthesis of new GM‐CSF receptors contributed to the re‐expression of GM‐CSF receptors after down‐regulation and it is possible that the GM‐CSF enhances the synthesis of its own receptors.