Direct interaction between Ras and the kinase domain of mitogen-activated protein kinase kinase kinase (MEKK1).
Mitogen-activated protein kinase kinase kinase (MEKK1) is a serine-threonine kinase that regulates sequential protein kinase pathways involving stress-activated protein kinases and mitogen-activated protein kinases. MEKK1 is activated in response to growth factor stimulation of cells and by expression of activated Ras. We demonstrate that the kinase domain of MEKK1 (MEKKCOOH) binds to GST-RasV12 in a GTP-dependent manner. Purified bacterially expressed MEKKCOOH binds to GST-RasV12(GTP gamma S) (GTP gamma S is guanosine 5'-3-O-(thio)triphosphate), demonstrating a direct interaction of the two proteins. A Ras effector domain peptide blocks the binding of MEKKCOOH to GST-RasV12(GTP gamma S). MEKKCOOH complexed with GST-RasV12(GTP gamma S) is capable of phosphorylating MEK1. These findings indicate that MEKK1 directly binds Ras.GTP. Thus, Ras interacts with protein kinases of both the Raf and MEKK families.
Russell
M
M
Division of Basic Sciences, National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado 80206, USA.
Lange-Carter
C A
CA
Johnson
G L
GL
D000818:Animals; D002461:Cell Line, Transformed; D002522:Chlorocebus aethiops; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019908:Proto-Oncogene Proteins c-raf; D011993:Recombinant Fusion Proteins / Q000378:metabolism
D010446:Peptide Fragments; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D017346:Protein Serine-Threonine Kinases; D019908:Proto-Oncogene Proteins c-raf