Receptor for TNFSF5/CD40LG (PubMed:31331973). Transduces TRAF6- and MAP3K8-mediated signals that activate ERK in macrophages and B cells, leading to induction of immunoglobulin secretion (By similarity). Monomer and homodimer. The variant form found in the bladder carcinoma cell line Hu549 does not form homodimers. Interacts with TRAF1, TRAF2, TRAF3, TRAF5 and TRAF6. Interacts with TRAF6 and MAP3K8; the interaction is required for ERK activation. Additional isoforms seem to exist. B-cells and in primary carcinomas. The disease is caused by variants affecting the gene represented in this entry. CD40 mutation db CD40 entry