The FMS-like tyrosine kinase 1 (FLT1), also known as vascular endothelial growth factor receptor 1 (VEGFR1), is a transmembrane receptor tyrosine kinase primarily involved in angiogenesis and vascular development. It binds ligands such as VEGF-A, VEGF-B, and placental growth factor (PlGF), regulating endothelial cell proliferation, migration, and survival. FLT1 plays dual roles: its membrane-bound form mediates signal transduction, while a soluble isoform (sFLT1) acts as a decoy receptor to modulate ligand availability. Dysregulation of FLT1 signaling is linked to pathological conditions, including cancer, diabetic retinopathy, and preeclampsia.
FLT1 antibodies are essential tools for studying these processes. Monoclonal or polyclonal antibodies targeting specific FLT1 epitopes are used in research applications like Western blotting, immunohistochemistry (IHC), and flow cytometry to quantify receptor expression, localization, and activation. Therapeutic FLT1-blocking antibodies have been explored to inhibit angiogenesis in cancers or ocular diseases by disrupting VEGF/FLT1 interactions. Conversely, agonistic antibodies or sFLT1-based therapies (e.g., aflibercept) aim to neutralize excess VEGF in conditions like age-related macular degeneration.
Despite its lower kinase activity compared to VEGFR2 (KDR), FLT1's unique ligand-binding profile and regulatory functions make it a critical target for both mechanistic studies and clinical interventions. Antibodies against FLT1 continue to advance our understanding of vascular biology and therapeutic strategies for angiogenesis-related diseases.