Regulation of connexin43 oligomerization is saturable.
We have used connexin constructs containing a C-terminal di-lysine-based endoplasmic reticulum (ER) retention/retrieval signal (HKKSL) transfected into HeLa cells to study early events in connexin oligomerization. Using this approach, we found that Cx43-HKKSL stably expressed at moderate levels by HeLa cells was retained in the ER and prevented from oligomerization. However, Cx43-HKKSL stably overexpressed by HeLa cells escaped from the ER and localized to a perinuclear region of the cell that included the Golgi apparatus. Overexpressed Cx43-HKKSL oligomerized into hexamers and also formed Triton X-100 insoluble, intracellular complexes that resembled gap junctions. Thus, the ability of HeLa cells to inhibit Cx43 oligomerization was saturable. HeLa cells stably overexpressing Cx43-HKKSL may provide a useful model system to evaluate pharmacologic agents and/or cDNAs encoding chaperones with the potential to regulate initial steps in Cx43 oligomerization.
Das Sarma
Jayasri
J
Department of Neurology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA, USA.
Das
Shamie
S
Koval
Michael
M
D002450:Cell Communication; D018031:Connexin 43 / Q000235:genetics* / Q000378:metabolism; D004151:Dipeptides / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D017629:Gap Junctions / Q000235:genetics / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008954:Models, Biological; D021382:Protein Sorting Signals / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection
D018031:Connexin 43; D004151:Dipeptides; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; C024575:lysyllysine