In contrast , expression of dominant negative mutants of Ras and Raf-1 , in these cells , did not have any effect on FcR -mediated nuclear factor activation , suggesting that the mitogen-activated protein kinase ( MAPK ) signaling pathway was not used by these receptors .
in contrast , expression of dominant negative mutants of ras and raf-1 , in these cells , did not have any effect on fcr -mediated nuclear factor activation , suggesting that the mitogen-activated protein kinase ( mapk ) signaling pathway was not used by these receptors .
O O O O O B-protein_family_or_group I-protein_family_or_group I-protein_family_or_group O B-protein_molecule O B-protein_molecule O O O O O O O O O O O B-protein_family_or_group O B-protein_family_or_group I-protein_family_or_group O O O O O B-protein_family_or_group I-protein_family_or_group I-protein_family_or_group O B-protein_family_or_group O O O O O O O O O O