Tan A, Bolscher J, Feltkamp C, Ploegh H
The Netherlands Cancer Institute, Division of Cellular Biochemistry, Amsterdam.
J Cell Biol. 1992 Mar;116(6):1357-67. doi: 10.1083/jcb.116.6.1357.
The involvement of GTP-binding proteins in the intracellular transport of the secretory glycoprotein alpha 1-antitrypsin was investigated in streptolysin O-permeabilized HepG2 cells. This permeabilization procedure allows ready access to the intracellular milieu of the membrane-impermeant, nonhydrolyzable GTP analog GTP gamma S. In streptolysin O-permeabilized HepG2 cells, the constitutive secretory pathway remains functional and is sensitive to GTP gamma S. Exposure of HepG2 cells to brefeldin A resulted in redistribution of Golgi-resident glycosyltransferases (including both alpha 2----3 and alpha 2----6 sialyltransferases) to the ER. This redistribution was sensitive to GTP gamma S. Our results suggest that GTP-binding proteins are involved in the regulation not only of the anterograde, but also of the retrograde, pathway.
在经链球菌溶血素O通透处理的HepG2细胞中,研究了GTP结合蛋白在分泌性糖蛋白α1-抗胰蛋白酶细胞内运输中的作用。这种通透处理方法使得能够方便地接触到膜不透性、不可水解的GTP类似物GTPγS的细胞内环境。在经链球菌溶血素O通透处理的HepG2细胞中,组成型分泌途径仍然具有功能,并且对GTPγS敏感。将HepG2细胞暴露于布雷菲德菌素A会导致高尔基体驻留糖基转移酶(包括α2----3和α2----6唾液酸转移酶)重新分布到内质网。这种重新分布对GTPγS敏感。我们的结果表明,GTP结合蛋白不仅参与顺行途径的调节,还参与逆行途径的调节。