title: The apoptosis-inducing granulocyte-macrophage colony-stimulating factor (GM-CSF) analog E21R functions through specific regions of the heterodimeric GM-CSF receptor and requires interleukin-1beta-converting enzyme-like proteases.
abstract: The granulocyte-macrophage colony-stimulating factor (GM-CSF) analog E21R induces apoptosis of hemopoietic cells. We examined the GM-CSF receptor subunit requirements and the signaling molecules involved. Using Jurkat T cells transfected with the GM-CSF receptor we found that both receptor subunits were necessary for E21R-induced apoptosis. Specifically, the 16 membrane-proximal residues of the alpha subunit were sufficient for apoptosis. This sequence could be replaced by the corresponding sequence from the interleukin-2 receptor common gamma subunit, identifying this as a conserved cytokine motif necessary for E21R-induced apoptosis. Cells expressing the alpha subunit and truncated betac mutants showed that the 96 membrane-proximal residues of betac were sufficient for apoptosis. E21R, in contrast to GM-CSF, did not alter tyrosine phosphorylation of betac, suggesting that receptor-associated tyrosine kinases were not activated. Consistent with this, E21R decreased the mitogen-activated protein kinase ERK (extracellular signal-regulated kinase). E21R-induced apoptosis was independent of Fas/APO-1 (CD95) and required interleukin-1beta-converting enzyme (ICE)-like proteases. In contrast, Bcl-2, which protects cells from growth factor deprivation-induced cell death, did not prevent this apoptosis. These findings demonstrate the GM-CSF receptor and ICE-like protease requirements for E21R-induced apoptosis.
authors.affiliation: Institute of Human Immunology, Hanson Centre for Cancer Research, IMVS, Adelaide, 5000 S.A., Australia.
authors.forename: P O
authors.initials: PO
authors.lastname: Iversen
authors.forename: T R
authors.initials: TR
authors.lastname: Hercus
authors.forename: B
authors.initials: B
authors.lastname: Zacharakis
authors.forename: J M
authors.initials: JM
authors.lastname: Woodcock
authors.forename: F C
authors.initials: FC
authors.lastname: Stomski
authors.forename: S
authors.initials: S
authors.lastname: Kumar
authors.forename: B H
authors.initials: BH
authors.lastname: Nelson
authors.forename: A
authors.initials: A
authors.lastname: Miyajima
authors.forename: A F
authors.initials: AF
authors.lastname: Lopez
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D020170:Caspase 1; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D003593:Cytoplasm / Q000201:enzymology; D015536:Down-Regulation / Q000187:drug effects; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases; D019169:Jurkat Cells; D020928:Mitogen-Activated Protein Kinases; D010766:Phosphorylation; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism*; D011994:Recombinant Proteins
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D007375:Interleukin-1; C098738:N-acetyl-tyrosyl-valyl-alanyl-aspartyl chloromethyl ketone; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D011994:Recombinant Proteins; C101659:granulocyte-macrophage colony-stimulating factor, Arg(21)-; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D003546:Cysteine Endopeptidases; D020170:Caspase 1