Arg777 plays a major role in the conformation of the colony-stimulating factor-1 receptor intracellular kinase domain.
A point mutation substituting Arg777 by Gln was obtained in a highly conserved region of the human colony-stimulating factor-1 receptor (CSF-1R) sequence. Constitutive expression of wild-type receptors in CHO cells confers susceptibility to CSF-1 for proliferation whereas the mutated receptors exhibited a 90% reduced efficiency in proliferation. We sought to determine the alterations intervening in the CSF-1 signal transduction of the Arg777Gln mutated receptor. We found that ligand binding and ligand-induced CSF-1R internalization were unaffected. CSF-1-induced receptor dimerization and autophosphorylation were impaired to the same extent as mitogen-activated protein kinase activation (90%). However, only phosphatidylinositol 3-kinase activation and ligand-induced receptor ubiquitination were abrogated by the mutation. These features probably reflect the inability of the mutated CSF-1R kinase domain to fold properly and hence to autophosphorylate and/or to associate correctly with transduction proteins. These data may indicate a role for the conserved regions of the RTK kinase domains in the stabilization of the intracellular domain conformation.
Schmid-Antomarchi
H
H
Unité de Recherches en Immunologie Moléculaire et Cellulaire, U. 364 INSERM, Faculté de Médecine, Nice, France.
Husson
H
H
Debant
A
A
Breittmayer
V
V
Ramos-Morales
F
F
Fischer
S
S
Rossi
B
B
D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D001120:Arginine / Q000235:genetics* / Q000502:physiology; D001665:Binding Sites / Q000235:genetics; D016466:CHO Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D006224:Cricetinae; D004705:Endocytosis; D004789:Enzyme Activation; D005973:Glutamine / Q000235:genetics; D006801:Humans; D016173:Macrophage Colony-Stimulating Factor / Q000378:metabolism / Q000494:pharmacology; D016297:Mutagenesis, Site-Directed / Q000235:genetics; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D017354:Point Mutation / Q000235:genetics; D011485:Protein Binding; D011487:Protein Conformation; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics; D017434:Protein Structure, Tertiary; D016184:Receptors, Colony-Stimulating Factor / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D014452:Ubiquitins / Q000378:metabolism
D016184:Receptors, Colony-Stimulating Factor; D014452:Ubiquitins; D005973:Glutamine; D016173:Macrophage Colony-Stimulating Factor; D001120:Arginine; D011494:Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases