B cell growth is controlled by phosphatidylinosotol 3-kinase-dependent induction of Rel/NF-kappaB regulated c-myc transcription.

Rel/NF-kappaB transcription factors regulate the division and survival of B lymphocytes. Here we show that B cells lacking NF-kappaB1 and c-Rel fail to increase in size upon mitogenic stimulation due to a reduction in induced c-myc expression. Mitogen-induced B cell growth, although not markedly impaired by FRAP/mTOR or MEK inhibitors, required phosphatidylinositol 3-kinase (PI3K) activity.