Description
Recombinant human soluble TEK was fused with the Fc part of human IgG1. The recombinant mature TEK/Fc is a disulfide-linked homodimeric protein. The soluble receptor protein consists of the full extracellular domain (Met1-Val730). TIE-1 (tyrosine kinase with Ig and EGF homology domains 1) and TEK (TIE2) comprise a receptor tyrosine kinase (RTK) subfamily with unique structural characteristics: two immunoglobulin-like domains flanking three epidermal growth factor (EGF)-like domains and followed by three fibronectin type III-like repeats in the extracellular region and a split tyrosine kinase domain in the cytoplasmic region. These receptors are expressed primarily on endothelial and hematopoietic progenitor cells and play critical roles in angiogenesis, vasculogenesis and hematopoiesis. Human TEK cDNA encodes a 1124 amino acid residue precursor protein with an 18 residue putative signal peptide, a 727 residue extracellular domain and a 354 residue cytoplasmic domain. Two ligands, angiopoietin 1 and angiopoietin 2, which bind TEK with high-affinity have been identified. Angiopoietin 2 has been reported to act as an antagonist for Angiopoietin 1. Mice engineered to over express Angiopoietin 2 or to lack Angiopoietin 1 or TEK display similar angiogenic defects