Alternative modes of GM-CSF receptor activation revealed using activated mutants of the common beta-subunit.
Granulocyte/macrophage colony-stimulating factor promotes growth, survival, differentiation, and activation of normal myeloid cells and plays an important role in myeloid leukemias. The GM-CSF receptor (GMR) shares a signaling subunit, beta(c), with interleukin-3 and interleukin-5 receptors and has recently been shown to induce activation of Janus kinase 2 (JAK2) and downstream signaling via formation of a unique dodecameric receptor complex. In this study we use 2 activated beta(c) mutants that display distinct signaling capacity and have differential requirements for the GMR alpha-subunit (GMR-alpha) to dissect the signaling pathways associated with the GM-CSF response. The V449E transmembrane mutant selectively activates JAK2/signal transducer and activator of transcription 5 and extracellular signal-regulated kinase (ERK) pathways, resulting in a high level of sensitivity to JAK and ERK inhibitors, whereas the extracellular mutant (FIDelta) selectively activates the phosphoinositide 3-kinase/Akt and IkappaKbeta/nuclear factorkappaB pathways. We also demonstrate a novel and direct interaction between the SH3 domains of Lyn and Src with a conserved proline-rich motif in GMR-alpha and show a selective requirement for Src family kinases by the FIDelta mutant. We relate the nonoverlapping nature of signaling by the activated mutants to the structure of the unique GMR complex and propose alternative modes of receptor activation acting synergistically in the mature liganded receptor complex.
Perugini
Michelle
M
Division of Haematology, Centre for Cancer Biology, SA Pathology, Adelaide, Australia.
Brown
Anna L
AL
Salerno
Diana G
DG
Booker
Grant W
GW
Stojkoski
Cvetan
C
Hercus
Timothy R
TR
Lopez
Angel F
AF
Hibbs
Margaret L
ML
Gonda
Thomas J
TJ
D'Andrea
Richard J
RJ
D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D004789:Enzyme Activation / Q000502:physiology*; D005434:Flow Cytometry; D047468:Immunoprecipitation; D015470:Leukemia, Myeloid, Acute / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D009154:Mutation; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor