HGF R, also known as Met (from N-methyl-N'-nitro-N-nitrosoguanidine induced), is a glycosylated receptor tyrosine kinase that plays a central role in epithelial morphogenesis and cancer development. HGF R is synthesized as a single chain precursor which undergoes posttranslational proteolytic cleavage. This generates a mature HGF R that is a disulfide-linked dimer composed of a 50 kD extracellular α chain and a 145 kD transmembrane β chain. 1,2 The extracellular domain (ECD) contains a seven bladed β- propeller sema domain, a cysteine-rich PSI/MRS region, and four Ig-like E-set domains, while the cytoplasmic region includes a tyrosine kinase domain. 3 The sema domain, which is formed by both the α and β chains of HGF R, mediates both ligand binding and receptor dimerization. 3,4 Ligand-induced tyrosine phosphorylation in the cytoplasmic region activates the kinase domain and provides docking sites for multiple SH2-containing molecules. 5,6 HGF stimulation induces HGF R downregulation via internalization and proteasome-dependent degradation. 7 In the absence of ligand, HGF R forms noncovalent complexes with a variety of membrane proteins including CD44v6, CD151, EGF R, Fas, integrin α 6/β4, plexins B1, B2, and B3, and MSP R/Ron. 8-15 Ligation of one complex component triggers activation of the other, followed by cooperative signaling effects. 8-15 Formation of some of these heteromeric complexes is a requirement for epithelial cell morphogenesis and tumor cell invasion. 8,12,13 HGF released from neighboring mesenchymal cells stimulates HGF R on undifferentiated epithelium and induces epithelial cell scattering and branching tubulogenesis. 16 Genetic polymorphisms, chromosomal translocation, overexpression, and additional splicing and proteolytic cleavage of HGF R have been described in a wide range of cancers. 1 Within the ECD, canine HGF R shares 85%-88% aa sequence identity with human, mouse and rat HGF R.
Source:Human CD33 signal peptide (Met 1-Ala 16), Canine HGF R, (Glu 25-Leu 935), HHHHHH; A DNA sequence encoding the signal peptide from human CD33 joined with the extracellular domain of canine HGF R (Glu 25-Leu 935; Accession # Q75ZY9) was fused with a 6X histidine tag at the C-terminus. The chimeric protein was expressed in a mouse myeloma cell line, NS0.
Molecular Mass:The mature recombinant canine HGF R/His is a disulfide-linked heterodimer. Based on N-terminal amino acid sequencing, the recombinant canine HGF R/His has two N-termini starting at Glu 25 and Ser 309 that correspond to the α and β chains, respectively. The predicted molecular mass for the α chain is approximately 32.6 kD, and that for the β chain is approximately 70.1 kD. As a result of glycosylation, in SDS-PAGE, the recombinant protein migrates as an approximately 130-150 kD protein under non-reducing conditions, and as approximately 42-47 kD (α-chain) and 90-100 kD (β−chain) proteins under reducing conditions.
Endotoxin Level:< 1.0 EU per 1 μg of the protein as determined by the LAL method.
Activity:Measured by its ability to bind rcaHGF with an estimated Kd < 0.8 nm
Storage and Stability:Lyophilized samples are stable for up to twelve months from date of receipt at -20°C. Upon reconstitution, this protein, in the presence of a carrier protein, can be stored under sterile conditions at 2-8°C for one month or at -20°C in a manual defrost freezer for three months without detectable loss of activity. Avoid repeated freeze-thaw cycles.
