Differentiation-linked changes in tyrosine phosphorylation, functional activity, and gene expression downstream from the granulocyte-macrophage colony-stimulating factor receptor.
The HL-60 model of myeloid maturation was used to test whether changes in signaling from the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor accompany maturation-related changes in cellular responses to GM-CSF. Receptor expression, tyrosine phosphorylation, functional activity, and c-fos gene expression were measured. Functional GM-CSF receptors were present throughout differentiation as both uninduced and dimethyl sulfoxide (DMSO)-induced HL-60 cells responded to GM-CSF, albeit in different ways. Uninduced promyelocytes proliferated in response to GM-CSF, whereas DMSO-induced cells lost the capacity to proliferate but did respond with increased expression of beta 2-integrins, enhanced respiratory burst activity, and metabolism of arachidonic acid. GM-CSF-stimulated upregulation of c-fos mRNA expression was not detected in immature cells but developed after 2 to 4 days with DMSO in line with a marked increase in responsiveness to stimulation with phorbol ester, showing that increased expression of c-fos is predominantly a feature of mature phagocytes. GM-CSF stimulated the tyrosine phosphorylation of a broadly similar range of proteins in both uninduced and DMSO-treated HL-60 cells, but protein bands were more heavily phosphorylated in DMSO-induced cells. Phosphorylation was rapid in onset and very transient in immature cells. Phosphorylation of several proteins, in particular a 130-kD band, was more sustained in DMSO-induced cells. These differences in signaling were not because of numerical differences in receptors, because reduction of GM-CSF concentration to trigger equivalent numbers of high-affinity receptors delayed the onset of phosphorylation in DMSO-induced cells. We conclude that there are maturation-related changes in signaling downstream from the GM-CSF receptor.
Roberts
P J
PJ
Department of Haematology, University College London Medical School, UK.
Khwaja
A
A
Lie
A K
AK
Bybee
A
A
Yong
K
K
Thomas
N S
NS
Linch
D C
DC
D016718:Arachidonic Acid / Q000378:metabolism; D018821:CD18 Antigens; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D015870:Gene Expression; D016762:Genes, fos; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D016023:Integrins / Q000096:biosynthesis; D007700:Kinetics; D015473:Leukemia, Promyelocytic, Acute; D010750:Phosphoproteins / Q000096:biosynthesis / Q000378:metabolism; D010766:Phosphorylation; D019000:Phosphotyrosine; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D013997:Time Factors; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism
D018821:CD18 Antigens; D016023:Integrins; D010750:Phosphoproteins; D012333:RNA, Messenger; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D013481:Superoxides; D019000:Phosphotyrosine; D016718:Arachidonic Acid; D014443:Tyrosine; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D004121:Dimethyl Sulfoxide