Before revision: This complex system (often referred to as the IGF "axis") consists of two cell-surface receptors (IGF1R and IGF2R), two ligands ( Insulin-like growth factor 1 ( IGF-1 ) and Insulin-like growth factor 2 ( IGF-2 ) ), a family of seven high-affinity IGF-binding proteins (IGFBP1 to IGFBP7), as well as associated IGFBP degrading enzymes, referred to collectively as proteases.
After revision: This complex system (often referred to as the IGF "axis") consists of two cell-surface receptors (IGF1R and IGF2R), two ligands ( Insulin-like growth factor 1 ( IGF-1 and IGF-2 ), a family of seven high-affinity IGF-binding proteins (IGFBP1 to IGFBP7), as well as associated IGFBP degrading enzymes, referred to collectively as proteases.