The Type-2 insulin-like growth factor receptor (IGF2R) is a ubiquitously expressed
integral glycoprotein with a molecular mass of 300 kDa. Four different classes of
ligands are presently known, binding to distinct sites at the extracytoplasmic receptor
domain: mannose 6-phosphate-containing lysosomal enzymes, the non-glycosylated IGF
II, retinoic acid, and urokinasetype plasminogen activator receptor. The intracellular
transport and functions of the IGF2R are determined by signal structures localized
in the cytoplasmic receptor domain interacting with different cytosolic and membrane-bound
proteins. The IGF2R gene is developmentally regulated. The coordinated expression
of IGF II and IGF2R in most mammalian tissues and gene targeting experiments suggest
a role of IGF2R in the control of extra-cellular IGF II concentration by receptor-mediated
endocytosis and subsequent degradation of the growth factor in lysosomes. Specific
alterations in the expression, activation and routing of both IGF2R and its ligands
in human and rodent tumors suggest that the IGF2R functions as a tumor suppressor.
Type-2 IGF Receptors (IGF2R) - Mannose 6-Phosphate Receptor - Binding Sites - Recycling
- Cytoplasmic Signals - Development - Imprinting - Mutations - Tumor
