Identification of a viability domain in the granulocyte/macrophage colony-stimulating factor receptor beta-chain involving tyrosine-750.
The granulocyte/macrophage colony-stimulating factor (GM-CSF) receptor (GMR) is a heterodimeric receptor expressed by myeloid lineage cells. In this study we have investigated domains of the GMR beta-chain (GMR beta) involved in maintaining cellular viability. Using a series of nested GMR beta deletion mutants, we demonstrate that there are at least two domains of GMR beta that contribute to viability signals. Deletion of amino acid residues 626-763 causes a viability defect that can be rescued with fetal calf serum (FCS). Deletion of residues 518-626, in contrast, causes a further decrement in viability that can be only partially compensated by the addition of FCS. GMR beta truncated proximal to amino acid 517 will not support long-term growth under any conditions. Site-directed mutagenesis of tyrosine-750 (Y750), which is contained within the distal viability domain, to phenylalanine eliminates all demonstrable tyrosine phosphorylation of GMR beta. Cell lines transfected with mutant GMR beta (Y750-->F) have a viability disadvantage when compared to cell lines containing wild-type GMR that is partially rescued by the addition of FCS. We studied signal transduction in mutant cell lines in an effort to identify pathways that might participate in the viability signal. Although tyrosine phosphorylation of JAK2, SHPTP2, and Vav is intact in Y750-->F mutant cell lines, Shc tyrosine phosphorylation is reduced. This suggests a potential role for Y750 and potentially Shc in a GM-CSF-induced signaling pathway that helps maintain cellular viability.
Inhorn
R C
RC
Division of Hematologic Malignancies, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
Carlesso
N
N
Durstin
M
M
Frank
D A
DA
Griffin
J D
JD
D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology*; D018797:Cell Cycle Proteins; D002460:Cell Line; D002470:Cell Survival; D004252:DNA Mutational Analysis; D004789:Enzyme Activation; D047908:Intracellular Signaling Peptides and Proteins; D053614:Janus Kinase 2; D051379:Mice; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D011487:Protein Conformation; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051567:Proto-Oncogene Proteins c-vav; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000235:genetics / Q000378:metabolism; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics / Q000502:physiology*; D011994:Recombinant Proteins; D017384:Sequence Deletion; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D013329:Structure-Activity Relationship; D014443:Tyrosine / Q000235:genetics
D018797:Cell Cycle Proteins; D047908:Intracellular Signaling Peptides and Proteins; D011518:Proto-Oncogene Proteins; D051567:Proto-Oncogene Proteins c-vav; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D011994:Recombinant Proteins; C496619:Vav1 protein, mouse; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2; D016392:Proto-Oncogene Proteins pp60(c-src); D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse; C509248:Ptpn6 protein, mouse