Rosorius O, Issinger O G, Braulke T
Institute for Biochemistry II, University of Göttingen, Federal Republic of Germany.
J Biol Chem. 1993 Oct 15;268(29):21470-3.
The cytoplasmic tail of the human 300-kDa mannose 6-phosphate receptor (MPR 300-CT) is an excellent substrate for casein kinase II in vitro. The phosphorylated MPR 300-CT was cross-linked by means of bis(sulfosuccinimidyl)suberate mainly to a cytosolic protein of 35 kDa (referred to as TIP 35) and to 35- and 91-kDa proteins salt-washed from bovine brain membranes. Gel filtration suggested that TIP 35 is part of a higher molecular mass complex of approximately 130-150 kDa. Inhibition studies, using non-phosphorylated and phosphorylated MPR 300-CT and cross-linking, indicate that the interaction with TIP 35 is phosphorylation-specific. Furthermore, TIP 35 was only cross-linked to the MPR 300-CT phosphorylated by casein kinase II whereas the MPR 300-CT phosphorylated by protein kinase A failed to cross-link to TIP 35. These results indicate that the cytoplasmic tail of the MPR 300 interacts with a cytosolic protein depending on the phosphorylation by a casein kinase II-like kinase. The cross-linking with salt-washed membrane proteins, however, is inhibited by non-phosphorylated MPR 300-CT, suggesting that different structural determinants in the MPR 300-CT interact with cytosol- and membrane-derived proteins.
人300 kDa甘露糖6 - 磷酸受体（MPR 300 - CT）的细胞质尾巴在体外是酪蛋白激酶II的优良底物。磷酸化的MPR 300 - CT通过双（磺基琥珀酰亚胺）辛二酸酯主要与一种35 kDa的胞质蛋白（称为TIP 35）以及从牛脑膜上用盐洗脱的35 kDa和91 kDa蛋白交联。凝胶过滤表明TIP 35是大约130 - 150 kDa的更高分子量复合物的一部分。使用未磷酸化和磷酸化的MPR 300 - CT以及交联进行的抑制研究表明，与TIP 35的相互作用具有磷酸化特异性。此外，TIP 35仅与经酪蛋白激酶II磷酸化的MPR 300 - CT交联，而经蛋白激酶A磷酸化的MPR 300 - CT未能与TIP 35交联。这些结果表明，MPR 300的细胞质尾巴与一种胞质蛋白相互作用，这取决于酪蛋白激酶II样激酶的磷酸化作用。然而，未磷酸化的MPR 300 - CT抑制了与用盐洗脱的膜蛋白的交联，这表明MPR 300 - CT中不同的结构决定簇与胞质和膜来源的蛋白相互作用。
