Majoul I, Sohn K, Wieland F T, Pepperkok R, Pizza M, Hillemann J, Söling H D
Abteilung Klinische Biochemie, Universität Göttingen, D-37070 Göttingen, Germany.
J Cell Biol. 1998 Nov 2;143(3):601-12. doi: 10.1083/jcb.143.3.601.
A cholera toxin mutant (CTX-K63) unable to raise cAMP levels was used to study in Vero cells the retrograde transport of the toxin A subunit (CTX-A-K63), which possesses a COOH-terminal KDEL retrieval signal. Microinjected GTP-gamma-S inhibits the internalization as well as Golgi-ER transport of CTX-A-K63. The appearance of CTX-A-K63 in the Golgi induces a marked dispersion of Erd2p and p53 but not of the Golgi marker giantin. Erd2p is translocated under these conditions most likely to the intermediate compartment as indicated by an increased colocalization of Erd2p with mSEC13, a member of the mammalian coat protein II complex. IgGs as well as Fab fragments directed against Erd2p, beta-COP, or p23, a new member of the p24 protein family, inhibit or block retrograde transport of CTX-A-K63 from the Golgi without affecting its internalization or its transport to the Golgi. Anti-Erd2p antibodies do not affect the binding of CTX-A to Erd2p, but inhibit the CTX-K63-induced translocation of Erd2p and p53.
一种无法提高环磷酸腺苷（cAMP）水平的霍乱毒素突变体（CTX-K63）被用于在非洲绿猴肾细胞（Vero细胞）中研究毒素A亚基（CTX-A-K63）的逆向转运，该亚基具有一个COOH末端KDEL回收信号。显微注射鸟苷-5'-三磷酸γ-硫酯（GTP-γ-S）可抑制CTX-A-K63的内化以及从高尔基体到内质网的转运。CTX-A-K63在高尔基体中的出现会导致内质网驻留蛋白2（Erd2p）和p53明显分散，但不会导致高尔基体标志物巨蛋白分散。在这些条件下，Erd2p最有可能转运到中间区室，这可通过Erd2p与哺乳动物II型被膜蛋白复合物成员mSEC13的共定位增加来表明。针对Erd2p、β-COP或p24蛋白家族新成员p23的免疫球蛋白（IgG）以及Fab片段可抑制或阻断CTX-A-K63从高尔基体的逆向转运，而不影响其内化或向高尔基体的转运。抗Erd2p抗体不影响CTX-A与Erd2p的结合，但可抑制CTX-K63诱导的Erd2p和p53的转运。
