TY - JOUR
T1 - Multisubunit assembly of an integral plasma membrane channel protein, gap junction connexin43, occurs after exit from the ER
AU - Musil, Linda S.
AU - Goodenough, Daniel A.
N1 - Funding Information:
Experiments with the /d/F and /d/G cell lines were conducted in the laboratory of Monty Krieger (Massachusetts Institute of Technology), and we are very grateful to him for providing these cells and especially to Dr. Abby Fisher for her expertise and advice in their use. We also thank Tom White and Roberto Bruuone for their invaluable help with the Xenopus oocyte experiments and Tom Wileman for his gift of the BFA (originally obtained from Dr. Jennifer Lippincott-Schwartz) used in preliminary experiments. This work was supported in part by grants GM-18974 and EY-02430 to D. A. G. from the National Institutes of Health. L. S. M. is a fellow of the Medical Foundation of Boston.
PY - 1993/9/24
Y1 - 1993/9/24
N2 - Connexin43 (Cx43) is an integral plasma membrane protein that forms gap junctions between vertebrate cells. We have used sucrose gradient fractionation and chemical cross-linking to study the first step in gap junction assembly, oligomerization of Cx43 monomers into connexon channels. In contrast with other plasma membrane proteins, multisubunit assembly of Cx43 was specifically and completely blocked when endoplasmic reticulum (ER)-to-Golgi transport was inhibited by 15°C incubation, carbonyl cyanide m-chlorophenylhydrazone, or brefeldin A or in CHO cell mutants with temperature-sensitive defects in secretion. Additional experiments indicated that connexon assembly occurred intracellularly, most likely in the trans-Golgi network. These results describe a post-ER assembly pathway for integral membrane proteins and have implications for the relationship between membrane protein oligomerization and intracellular transport.
AB - Connexin43 (Cx43) is an integral plasma membrane protein that forms gap junctions between vertebrate cells. We have used sucrose gradient fractionation and chemical cross-linking to study the first step in gap junction assembly, oligomerization of Cx43 monomers into connexon channels. In contrast with other plasma membrane proteins, multisubunit assembly of Cx43 was specifically and completely blocked when endoplasmic reticulum (ER)-to-Golgi transport was inhibited by 15°C incubation, carbonyl cyanide m-chlorophenylhydrazone, or brefeldin A or in CHO cell mutants with temperature-sensitive defects in secretion. Additional experiments indicated that connexon assembly occurred intracellularly, most likely in the trans-Golgi network. These results describe a post-ER assembly pathway for integral membrane proteins and have implications for the relationship between membrane protein oligomerization and intracellular transport.
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U2 - 10.1016/0092-8674(93)90728-9
DO - 10.1016/0092-8674(93)90728-9
M3 - Article
C2 - 7691412
AN - SCOPUS:0027364529
SN - 0092-8674
VL - 74
SP - 1065
EP - 1077
JO - Cell
JF - Cell
IS - 6
ER -