EGFR/LGR5 Antibodies

Target Information

EGFR, epidermal growth factor receptor, is a receptor tyrosine kinases that signals in response to various growth factors. Overexpression has been linked to numerous types of cancer and EGFR is the target of both biological and small molecular therapeutics. EGFR is encoded by the EGFR gene located on chromosome 7 in humans. EGFR belongs to the HER/ERbB family of proteins that includes three other receptor tyrosine kinases, ERbB2, ERbB3, ERbB4. EGFR is a transmembrane receptor and binding of its cognate ligands such as EGF (Epidermal Growth Factor) and TGF alpha (Transforming Growth Factor alpha) to the extracellular domain leads to EGFR dimerization followed by autophosphorylation of the tyrosine residues in the cytoplasmic domain. Overexpression is observed in tumors of the head and neck, brain, bladder, stomach, breast, lung, endometrium, cervix, vulva, ovary, esophagus, stomach and in squamous cell carcinoma.

G protein-coupled receptor GPR49 has been reported to be expressed in brain, skeletal muscle, placenta, and spinal cord. ESTs have been isolated from normal human brain (amygdala), embryo, and placenta libraries and from human germ cell, uterus, and brain libraries. G-protein Coupled Receptors (GPCRs) comprise one of the largest families of signaling molecules with more than a thousand members currently predicted to exist. All GPCRs share a structural motif consisting of seven membrane-spanning helices, and exist in both active and inactive forms. An array of activating ligands participate in the conformation of GPCRs which leads to signaling via G-proteins and downstream effectors. Ongoing studies have also shown the vast series of reactions which participate in the negative regulation of GPCRs. This "turn-off" activity has tremendous implications for the physiological action of the cell, and continues to drive pharmacological research for new drug candidates. Two blockbuster drugs which have been developed as GPCR-targeted pharmaceuticals are Zyprexa (Eli Lilly) and Claritin (Schering-Plough) which have multi-billion dollar shares of the mental health and allergy markets, respectively.