Rosorius O, Issinger O G, Braulke T
Institute for Biochemistry II, University of Göttingen, Germany.
Biochem Biophys Res Commun. 1996 Apr 25;221(3):525-30. doi: 10.1006/bbrc.1996.0630.
The cytoplasmic tail of the 300 kDa mannose 6-phosphate receptor (MPR 300-CT) is thought to play an important role in sorting and targeting of lysosomal enzymes and the insulin-like growth factor II along the biosynthetic and endocytic pathway. In this study a brain specific 91 kDa protein and a 35 kDa protein salt-washed from membranes (referred as TIP 91-M and TIP 35-M) were found to interact with the cytoplasmic receptor tail as assayed by cross-linkage with recombinant [32P] labeled MPR 300-CT. Subcellular fractionation revealed a distinct pattern of distribution of TIP 35-M and TIP 91-M in microsomal and synaptosomal fractions. Furthermore, the formation of cross-link complexes with membrane proteins appeared to be developmentally and regionally regulated in the brain and inhibited upon ATP hydrolysis. The data suggest the requirement of specific protein interactions for MPR 300 functions in neuronal cells.
300kDa甘露糖6-磷酸受体（MPR 300-CT）的细胞质尾巴被认为在沿着生物合成和内吞途径对溶酶体酶及胰岛素样生长因子II进行分选和靶向定位中发挥重要作用。在本研究中，通过与重组[32P]标记的MPR 300-CT交联分析发现，一种从膜上盐洗下来的脑特异性91kDa蛋白和35kDa蛋白（称为TIP 91-M和TIP 35-M）能与细胞质受体尾巴相互作用。亚细胞分级分离显示TIP 35-M和TIP 91-M在微粒体和突触体组分中有不同的分布模式。此外，与膜蛋白形成交联复合物的过程似乎在脑中受到发育和区域调控，并且在ATP水解时受到抑制。这些数据表明在神经元细胞中MPR 300功能需要特定的蛋白质相互作用。
