| First Author | Zhu Z | Year | 2019 |
| Journal | Life Sci Alliance | Volume | 2 |
| Issue | 6 | PubMed ID | 31767615 |
| Mgi Jnum | J:287219 | Mgi Id | MGI:6391900 |
| Doi | 10.26508/lsa.201900506 | Citation | Zhu Z, et al. (2019) The AKT isoforms 1 and 2 drive B cell fate decisions during the germinal center response. Life Sci Alliance 2(6) |
| abstractText | The PI3K pathway is integral for the germinal center (GC) response. However, the contribution of protein kinase B (AKT) as a PI3K effector in GC B cells remains unknown. Here, we show that mice lacking the AKT1 and AKT2 isoforms in B cells failed to form GCs, which undermined affinity maturation and antibody production in response to immunization. Upon B-cell receptor stimulation, AKT1/2-deficient B cells showed poor survival, reduced proliferation, and impaired mitochondrial and metabolic fitness, which collectively halted GC development. By comparison, Foxo1 (T24A) mutant, which cannot be inactivated by AKT1/2 phosphorylation and is sequestered in the nucleus, significantly enhanced antibody class switch recombination via induction of activation-induced cytidine deaminase (AID) expression. By contrast, repression of FOXO1 activity by AKT1/2 promoted IRF4-driven plasma cell differentiation. Last, we show that T-cell help via CD40, but not enforced expression of Bcl2, rescued the defective GC response in AKT1/2-deficient animals by restoring proliferative expansion and energy production. Overall, our study provides mechanistic insights into the key role of AKT and downstream pathways on B cell fate decisions during the GC response. |
