it is well-established that the ci-mpr binds mannose 6-phosphate but there is a growing body of evidence that suggests the ci-mpr also binds to unglycosylated igf-ii. it is thought that when the ci-mpr is present on the cell surface, domain 11 will bind to any igf-ii free in the extracellular matrix. the receptor is then rapidly internalised, along with igf-ii, through a yskv motif present in the ci-mpr’s cytoplasmic tail. igf-ii will then be targeted to the lysosome where it will be degraded. this regulates the level of free igf-ii in the body.