Neuregulin 4 (NRG4)

The neuregulins, including NRG4, activate type-1 growth factor receptors (EGFR) to initiating cell-to-cell signaling through tyrosine phosphorylation.Loss of expression of NRG4 is frequently seen in advanced bladder cancer while increased NRG4 expression correlates to better survival.By searching databases for sequences similar to NRG1, Harari et al. (1999) identified an Nrg4 EST clone originating from a mouse liver cDNA library.The deduced 115-amino acid protein has a putative N-terminal EGF-like extracellular domain with 2 N-glycosylation sites, followed by a transmembrane region, and a short C-terminal cytoplasmic tail with another N-glycosylation site. It also has 6 cysteines predicted to form 3 disulfide bridges within the extracellular domain.