Betacellulin

Betacellulin (BTC) is a member of the epidermal growth factor (EGF) family which was originally identified as a secreted growth factor from pancreatic β-cell insulinomas. BTC is synthesized in a wide range of tissues of the adult body and in a large number cultured cells, including smooth muscle cells and epithelial cells. BTC has a high affinity and specificity for ErbB1/EGFR and ErbB4 and induces the growth of certain epithelial cell types. Homologous or heterologous dimers of ErbB family receptor are then formed to activate signal transduction pathways, such as PI3K/PDK1/Akt and RAS/RAF/MEK/Erk, leading to a series of biological effects. BTC has been implicated in a number of physiologic processes, including β-cell proliferation, keratinocyte proliferation and angiogenesis. BTC acts as an important regulator of ovarian follicle development, and can stimulate oocyte maturation and cumulus expansion.