To better understand this mechanism, the research group focused on the signaling of the extracellular signal-regulated kinases (ERK), intracellular signaling molecules known to play an important role in the cell cycle and survival of immune cells.
Hoping to glean insights into the role of ERKs in B cell differentiation into plasma cells, the researchers generated mice deficient in two different ERKs, ERK1 and ERK2, and studied the effect of this deficiency on the fate of B cells.
They found that ERKs are in fact essential to B cell differentiation: B cells in mice without these key molecules were unable to form plasma cells.
The researchers further traced this observation to a gene called Prdm1 encoding the protein BLIMP-1, increased expression of which leads to differentiation and proliferation of plasma cells in B cell immune response.
ERKs, they discovered, phosphorylate the transcription factor Elk1, which leads to expression of Blimp-1.