| First Author | Meyer C | Year | 2001 |
| Journal | J Cell Sci | Volume | 114 |
| Issue | Pt 24 | Pages | 4469-76 |
| PubMed ID | 11792812 | Mgi Jnum | J:73685 |
| Mgi Id | MGI:2156276 | Doi | 10.1242/jcs.114.24.4469 |
| Citation | Meyer C, et al. (2001) Mu1A deficiency induces a profound increase in MPR300/IGF-II receptor internalization rate. J Cell Sci 114(Pt 24):4469-76 |
| abstractText | The mannose-6-phosphate/IGF-II receptor MPR300 mediates sorting of lysosomal enzymes from the trans-Golgi network to endosomes and endocytosis of hormones, for example, of IGF-II. We analyzed transport of MPR300 in mu1A-adaptin-deficient fibroblasts, which lack a functional AP-1 clathrin adaptor complex. In mu1A-adaptin-deficient fibroblasts, the homologous MPR46 accumulates in endosomes due to a block in retrograde transport to the trans-Golgi network. The MPR300-mediated endocytosis is markedly enhanced. We demonstrate that the seven-fold increase in endocytosis is not associated with an increased steady-state concentration of receptors at the plasma membrane, but with an increased internalization rate of MPR300. Internalization of other receptors that are also endocytosed by AP-2 is not affected. More MPR300 receptors are found in clathrin-coated pits of the plasma membrane, whereas outside coated-areas, more MPR300 are concentrated in clusters and all intracellular receptors reside in endosomes, which are in equilibrium with the plasma membrane. Thus AP-1-mediated transport of MPR300 from endosomes to the TGN controls indirectly the recycling rate of the receptor between the plasma membrane and endosomes. |
