TNFRSF13C

• OMIM: 606 269
• UniProt: Q96RJ3

The BAFF receptor ( BAFF-R ) is a membrane protein in the B-cells of mammals. It is the most important receptor for the cytokine BAFF and is adjacent to the B cell receptor is the most important receptor in order to provide survival signals to B cells. The receptor is expressed on mature B cells. Its expression is up-regulated during the course of B-cell development. This happens in the transition stage when immature B cells to mature B cells. Mutations in TNFRSF13C gene can cause human congenital immunodeficiency ( CVID4 ).

Signal line by Baff receptor

Stimulation of the BAFF- receptor leads to the activation of the alternative NF-KB pathway (NF- κB2 ). Also weak NF- κB1 is activated by the BAFF- receptor. However, this is more affected by TACI, a receptor that also binds Baff.

The Baff receptor also binds to TRAF3, which with the kinase NIK (NF -kB inducing kinase) interacts. TRAF3 induces the degradation of NIK, which results in a reduced activity of NF- κB2. Therefore, this interaction is at first sight inconsistent with the shown activation of NF- κB2 by Baff receptor. One possible model that would explain this contradiction, is a degradation of TRAF3 by the binding of Baff Baff to the receptor. This would NIK stabilized and the alternative NF- κB2 pathway can be activated. In hitherto misunderstood ways Baff also activates PI3K and thus protein kinase B ( AKT also ). The activation of this kinase in turn results in the activation on the one hand and on the other hand, Mcl-1, and thus the mTORC1 mTOR complex. MTORC1 the complex is essential for protein synthesis, Mcl -1 is a member of the Bcl -2 family and ensures the survival of B- cells and T - cells.

BAFF receptor deficiency in mice

Mice that are deficient for the BAFF- receptor show a phenotype similar to mice who are deficient in the cytokine Baff. Among other animals lack the majority of the peripheral B cells.