Aggregation of the FcεRI in mast cells induces the synthesis of Fos-interacting protein and increases its DNA binding activity: The dependence on protein kinase C-β

The ability of c-Fos to dimerize with various proteins creates transcription complexes which can exert their regulatory function on a variety of genes. One of the transcription factors that binds to c-Fos is the newly discovered Fos-interacting protein (FIP). In this report we present evidence for the regulation of the synthesis of FIP by a physiological stimulus. We found that the aggregation of the mast cell high affinity receptor for IgE (FcεRI) induced the synthesis of FIP and increased its DNA binding activity. Moreover, down-regulation of the isoenzyme protein kinase C-β (PKC-β) by a specific antisense phosphorothioate oligonucleotide resulted in profound inhibition of FIP-Fos DNA binding activity. Thus, aggregation of the FcεRI on mast cells elicits a PKC-β dependent signaling pathway which regulates FIP-Fos DNA binding activity.