The DBB domain is named from the Drosophila (Downstream of FGFR - Dof, also known as Heartbroken or Stumps) protein, the BANKS and BCAP, both signalling in B-cell pathway, proteins. This domain defines a minimal region required for mediating Dof dimerisation. Since this domain can interact both with itself and with a region in the C-terminal part of the molecule, it may mediate either intermolecular or intramolecular interactions [1]. Mutants lacking this domain disrupt FGFR signal transduction and fibroblast growth-factor signalling [2]. The DBB domain of BCAP mediates BCAP TIR dimerization and negatively regulates TLR signalling [3].

1: Isolation of proteins that interact with the signal transduction molecule Dof and identification of a functional domain conserved between Dof and vertebrate BCAP. Battersby A, Csiszar A, Leptin M, Wilson R; J Mol Biol. 2003;329:479-493. PMID:12767830

2: A functional domain of Dof that is required for fibroblast growth factor signaling. Wilson R, Battersby A, Csiszar A, Vogelsang E, Leptin M; Mol Cell Biol. 2004;24:2263-2276. PMID:14993266

3: Negative Regulation of TLR Signaling by BCAP Requires Dimerization of Its DBB Domain. Lauenstein JU, Scherm MJ, Udgata A, Moncrieffe MC, Fisher DI, Gay NJ; J Immunol. 2020;204:2269-2276. PMID:32198144