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.
Retrograde transport from the Golgi region to the endoplasmic reticulum is sensitive to GTP gamma S.
A Tan, J Bolscher, C Feltkamp, H Ploegh; Retrograde transport from the Golgi region to the endoplasmic reticulum is sensitive to GTP gamma S.. J Cell Biol 15 March 1992; 116 (6): 1357–1367. doi: https://doi.org/10.1083/jcb.116.6.1357
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