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J. Exp. Med.,
Volume 188, Number 7, October 5, 1998 1287-1295
2 in Extracellular Signal-regulated Kinase, c-Jun
NH2-terminal Kinase, and p38 Mitogen-activated Protein
Kinase Activation by the B Cell Antigen Receptor
By


From the * Department of Molecular Genetics, Institute for Liver Research, Kansai Medical University,
Moriguchi 570-8506, Japan; the Mitogen-activated protein (MAP) kinase family members, including extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase ( JNK), and p38 MAP kinase, have been implicated in coupling the B cell antigen receptor (BCR) to transcriptional responses. However, the
mechanisms that lead to the activation of these MAP kinase family members have been poorly
elucidated. Here we demonstrate that the BCR-induced ERK activation is reduced by loss of
Grb2 or expression of a dominant-negative form of Ras, RasN17, whereas this response is not
affected by loss of Shc. The inhibition of the ERK response was also observed in phospholipase
C (PLC)-
Department of Microbiology, University of Washington, Seattle,
Washington 98195; and the § Department of Medicine and Pharmacology, Columbia University
College of Physicians and Surgeons, New York 10032
2-deficient DT40 B cells, and expression of RasN17 in the PLC-
2-deficient cells
completely abrogated the ERK activation. The PLC-
2 dependency of ERK activation was
most likely due to protein kinase C (PKC) activation rather than calcium mobilization, since
loss of inositol 1,4,5-trisphosphate receptors did not affect ERK activation. Similar to cooperation of Ras with PKC activation in ERK response, both PLC-
2-dependent signal and GTPase are required for BCR-induced JNK and p38 responses. JNK response is dependent on
Rac1 and calcium mobilization, whereas p38 response requires Rac1 and PKC activation.
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