title: c-Cbl tyrosine kinase-binding domain mutant G306E abolishes the interaction of c-Cbl with CD38 and fails to promote retinoic acid-induced cell differentiation and G0 arrest.
abstract: Retinoic acid (RA) causes HL-60 human myeloblastic leukemia cell myeloid differentiation that is dependent on MAPK signaling. The process is propelled by c-Cbl, which binds the CD38 receptor as part of a signaling complex generating MAPK signaling. Here we report that the capability of c-Cbl to do this is lost in the G306E tyrosine kinase-binding domain mutant. Unlike wild-type (WT) c-Cbl, the G306E mutant c-Cbl fails to propel RA-induced differentiation, and disrupts the normal association with CD38. The G306E mutant does, like WT c-Cbl, co-immunoprecipitate with Vav, Slp-76, and p38. But unlike WT c-Cbl, does not cause MAPK signaling. In contrast, the C381A Ring finger domain mutant functions like WT c-Cbl. It binds CD38 and is part of the same apparent c-Cbl/Slp-76/Vav/p38 signaling complex. The C381A mutant causes MAPK signaling and propels RA-induced differentiation. In addition to HL-60 cells and their WT or mutant c-Cbl stable transfectants, the c-Cbl/Vav/Slp-76 complex is also found in NB4 cells where c-Cbl was previously also found to bind CD38. The data are consistent with a model in which the G306E mutant c-Cbl forms a signaling complex that includes Slp-76, Vav, and p38; but does not drive MAPK signaling because it fails to bind the CD38 receptor. Without the G306E mutation the c-Cbl unites CD38 with the signaling complex and delivers a MAPK signal that drives RA-induced differentiation. The results demonstrate the importance of the Gly306 residue in the ability of c-Cbl to propel RA-induced differentiation.
authors.affiliation: Department of Biomedical Sciences, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Miaoqing
authors.initials: M
authors.lastname: Shen
authors.forename: Andrew
authors.initials: A
authors.lastname: Yen
mesh_terms: D051997:ADP-ribosyl Cyclase 1 / Q000235:genetics / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D019943:Amino Acid Substitution; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D018922:HL-60 Cells; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D020125:Mutation, Missense; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000235:genetics; D050721:Proto-Oncogene Proteins c-cbl / Q000235:genetics / Q000378:metabolism*; D051567:Proto-Oncogene Proteins c-vav / Q000235:genetics / Q000378:metabolism; D016192:Resting Phase, Cell Cycle / Q000187:drug effects* / Q000235:genetics; D014212:Tretinoin / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000970:Antineoplastic Agents; D008562:Membrane Glycoproteins; D046912:Multiprotein Complexes; D010750:Phosphoproteins; D051567:Proto-Oncogene Proteins c-vav; C092947:SLP-76 signal Transducing adaptor proteins; D014212:Tretinoin; D050721:Proto-Oncogene Proteins c-cbl; D048051:p38 Mitogen-Activated Protein Kinases; C498154:CD38 protein, human; D051997:ADP-ribosyl Cyclase 1; C067419:CBL protein, human