Multisubunit assembly of an integral plasma membrane channel protein, gap junction connexin43, occurs after exit from the ER

Linda S. Musil, Daniel A. Goodenough

Research output: Contribution to journalArticlepeer-review

380 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)1065-1077
Number of pages13
JournalCell
Volume74
Issue number6
DOIs
StatePublished - Sep 24 1993

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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