c-erbB3, Fc Chimera, Recombinant, Murine (HER 3, ErbB3)

ErbB3, also called Her3 (human epidermal growth factor receptor 3) in humans, is a type I transmembrane glycoprotein that is a member of the ErbB family of tyrosine kinase receptors named for a viral oncogene. ErbB family members serve as receptors for the EGF family of growth factors. Mouse ErbB3 contains a 19 amino acid (aa) signal sequence, a 622 aa extracellular domain (ECD), a 24 aa transmembrane region, and a 677 aa cytoplasmic domain. Human ErbB3 has four isoforms created by intron read-through and truncation of the molecule. Three of these are secreted and at least one can inhibit ErbB3 activity. Little information is available concerning mouse ErbB3 isoforms. The mouse ErbB3 ECD shares 97%, 93%, 92%, 91%, 89% and 88% aa identity with rat, human, cow, horse, dog and opossum ErbB3, respectively. ErbB3 is found in epithelial cell layers of gastrointestinal, reproductive, urinary, endocrine and nervous systems, skin and muscle. Among ErbB family members, only ErbB3 lacks a working kinase domain, requiring heterodimerization with another ErbB receptor for signaling. The heterodimer of ErbB3 with ErbB2, which has no known ligands of its own, is expressed in the majority of breast, skin, ovary and gastrointestinal tumors and transduces a highly mitogenic signal in response to neuregulin 1 (NRG1, heuregulin 1) or NRG2.3, 7-9 These ligands also bind ErbB4.1 Signaling is aided by the six consensus binding motifs for the SH2 domain and one for the SH3 domain of the regulatory p85 subunit of phosphoinositide 3-kinase.10, 11 Deletion studies in mice demonstrate non-redundant roles for ErbB3 in development of Schwann cells, neural crest cells and heart valves.12, 13 ErbB3, ErbB2 and neuregulin are all required for formation of the sympathetic nervous system. (14), Source: A DNA sequence encoding the extracellular domain of mouse ErbB3 (Ser 20-His 641, Accession # Q61526) was fused at the C-terminus to the Fc region of mouse IgG2A via a peptide linker. The chimeric protein was expressed in a mouse myeloma cell line, NS0. Activty: Measured by its ability to bind rhNRG1-Beta1 extracellular domain with an estimated KD ~15nM. Applications: Suitable for use in Western Blot. Other applications not tested. Recommended Dilution: Western Blot: 95.6kD protein migrates as an ~ 120-135kD protein in SDS-PAGE under reducing conditions., Optimal dilutions to be determined by the researcher. Storage and Stability: Lyophilized powder may be stored at 4°C for short-term only. Reconstitute with sterile PBS and store at -20°C. Reconstituted product is stable for 3 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.