EGFR

EGFR sits in the cell membrane with an outside portion that grabs epidermal growth factor family ligands. When one of these ligands binds, the receptor shifts shape and pairs up with another EGFR molecule, switching on the kinase inside the cell. The active kinase adds phosphate tags that recruit helpers like GRB2 and SHC. Those helpers route the signal into MAPK, PI3K-AKT, and STAT pathways, telling the cell to grow, survive, or adjust to its environment. Cells calm the signal by pulling EGFR into endosomes or tagging it for recycling. Antibodies, small molecules, and new protein binders that clamp onto EGFR can block ligand access, lock the kinase in an off state, or flag the receptor for degradation. Those different binder modes help labs test resistance mutations and design combination regimens that keep EGFR-driven tumors from escaping.