The kit recognizes human VEGFR1 (vascular endothelial growth factor receptor 1, fms-like tyrosine kinase 1, FLT1) and the antibodies are directed against the extracellular domain and can recognize both membrane-bound and soluble forms of VEGFR1, with approximate molecular weights of 180 kDa and 90 kDa, respectively. Mice lacking expression of VEGFR1 have disorganized vasculature and die in utero, however angiogenesis does not require the tyrosine kinase activity of VEGFR1 as expression of a membrane-bound form lacking the tyrosine kinase domain allows normal development. Although fertile and viable, mice lacking the tyrosine kinase domain of VEGFR1 do have a defect in the migration of macrophages. The soluble form of VEGFR1 can be detected in the serum of normal patients, and elevated levels of soluble VEGFR1 in pregnant women is associated with preeclampsia. Several tumor cell lines have been reported to express membrane-bound VEGFR1, including malignancies of hematopoietic origin. For research use only. Not for diagnostic or therapeutic procedures.
