Differential oligomerization of endoplasmic reticulum-retained connexin43/connexin32 chimeras.
To examine early events in connexin oligomerization, we made connexin constructs containing a C-terminal di-lysine based endoplasmic reticulum (ER) retention/retrieval signal (HKKSL). Previously, we found that both Cx32-HKKSL and Cx43-HKKSL were retained in the ER. However, Cx32-HKKSL oligomerized into hexameric hemichannels, but Cx43-HKKSL was retained as an apparent monomer. To define elements that prevent Cx43-HKKSL oligomerization in the ER, we made a series of HKKSL-tagged Cx43/Cx32 chimeras. When expressed by HeLa cells, some chimeras were retained in the ER as apparent monomers, whereas others oligomerized in the ER. To date, the second and third transmembrane domains and the cytoplasmic loop domain provide the minimal sufficient Cx43 element to inhibit ER oligomerization.
Maza
Jose
J
University of Pennsylvania School of Medicine, Department of Physiology, Philadelphia, PA 19104, USA.
Mateescu
Madalina
M
Das Sarma
Jayasri
J
Koval
Michael
M
D000818:Animals; D002450:Cell Communication / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism; D002678:Chimera / Q000378:metabolism; D018031:Connexin 43 / Q000378:metabolism*; D017630:Connexins / Q000378:metabolism*; D019281:Dimerization; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D017629:Gap Junctions / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D021382:Protein Sorting Signals / Q000502:physiology; D021381:Protein Transport / Q000502:physiology; D051381:Rats; D000097002:Gap Junction beta-1 Protein
D018031:Connexin 43; D017630:Connexins; D021382:Protein Sorting Signals; D000097002:Gap Junction beta-1 Protein