Disruption of fnip1 reveals a metabolic checkpoint controlling B lymphocyte development.

Publication Type:

Journal Article


Immunity, Volume 36, Issue 5, p.769-81 (2012)


2012, Clinical Research Division, June 2012


The coordination of nutrient and energy availability with cell growth and division is essential for proper immune cell development and function. By usingĀ a chemical mutagenesis strategy in mice, we identified a pedigree that has a complete block in B cell development at the pre-B cell stage resulting from a deletion in the Fnip1 gene. Enforced expression of an immunoglobulin transgene failed to rescue B cell development. Whereas essential pre-B cell signaling molecules were activated normally in Fnip1-null pre-B cells, the metabolic regulators AMPK and mTOR were dysregulated, resulting in excessive cell growth and enhanced sensitivity to apoptosis in response to metabolic stress (pre-B cell receptor crosslinking, oncogene activation). These results indicate that Folliculin-interacting protein 1 (Fnip1) is vital for B cell development and metabolic homeostasis and reveal a metabolic checkpoint that may ensure that pre-B cells have sufficient metabolic capacity to support division, while limiting lymphomagenesis caused by deregulated growth.