Betacellulin antibody [34362.11]

Betacellulin (BTC) is a heparin-binding member of the EGF family of growth factors that includes epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), amphiregulin (AR), heparin-binding EGF-like growth factor (HB-EGF), and the various heregulins (HRG). These growth factors bind to the EGF receptor and share at least 28 % sequence identity and 100% conservation of the 6 cysteine residue positions in the mature peptide sequence. Recombinant human betacellulin cDNA encodes an 80 amino acid residue polypeptide 7 with a predicted molecular mass of approximately 9.5 kDa. Betacellulin (BTC) was originally isolated as a 32 kDa glycoprotein from the conditioned media of mouse pancreatic beta tumor cells. It is capable of stimulating the proliferation of 3T3 cells, retinal pigment epithelial cells, and smooth muscle cells. The cDNA that encodes human BTC was cloned from a human breast adenocarcinoma cell line (MCF-7). Betacellulin is synthesized as a transmembrane precursor protein and then cleaved to release three types of soluble BTC forms (full length plus two amino-terminal truncation sites), all of which are equally bioactive. Human and mouse precursor forms of BTC exhibit 79 % amino acid sequence identity. Betacellulin is a unique EGF family member in that it binds with high affinity to EGF receptor, ErbB-1, and ErbB-4. Overexpression of betacellulin with ErbB-3 and ErbB-4 are linked to human endometrial adenocarcinoma. 2 Betacellulin has a role in the growth and differentiation of islet cells in the human pancreas.5 Betacellulin is produced in a wide variety of tissues, cultured cells, and various body fluids including milk. It is highly expressed in pancreas as well as liver, kidney, and small intestine. Betacellulin can also be found in lower abundance in testis, ovary, lung, and colon. BTC mRNA has not been found in brain, placenta, spleen, thymus, or peripheral blood leukocytes.