Department of Internal Medicine, University of South Florida, and H. Lee Moffitt Cancer Center and Research Institute, Tampa 33612, USA.
GM-CSF interacts with the low affinity GM-CSF receptor alpha-subunit, which leads to high affinity association with the alpha-subunit/common beta-subunit complex and transduction of intracellular signals leading to proliferation, differentiation, and/or activation of hemopoietic cells, predominantly in the neutrophil and monocyte/macrophage lineages. Several alternative splicing-derived variants of the GM-CSF receptor alpha-subunit have been described previously by this and other laboratories. A newly discovered alternative-splicing derived variant was isolated from the peripheral blood mononuclear cells of a patient with juvenile myelomonocytic leukemia. This variant lacks 397 base pairs corresponding to exons 8-11 of the wild type GM-CSF receptor alpha-subunit cDNA and potentially encodes a 233 amino acid protein lacking a membrane-anchoring domain and creating the fourth known potential soluble isoform of the alpha-subunit of the GM-CSF receptor.