The carboxy-terminal tail of connexin43 gap junction protein is sufficient to mediate cytoskeleton changes in human glioma cells.
Connexin43 (Cx43) is a ubiquitously expressed member of the gap junction protein family that mediates gap junction intercellular communication (GJIC) by allowing exchange of cytosolic materials. Previous studies have used Cx43 truncated at the cytoplasmic tail (C-tail) to demonstrate that the C-tail is essential to regulate cell growth and motility. Therefore, the aim of our study was to delineate the respective role of the truncated Cx43 and the C-tail in mediating Cx43-dependent signaling. A truncated Cx43 expressing the channel part of the protein (TrCx43, amino acid 1-242) and a construct encompassing only the C-tail from amino acid 243 (243Cx43) were transduced into LN18 human glioma cells. Our results showed that the ability of Cx43 to suppress growth was independent of GJIC as assessed by dye transfer, but was dependent on the presence of a rigid extracellular matrix. We further demonstrated that the C-tail alone is sufficient to promote motility. Surprisingly, Cx43 is also able to increase migration in the absence of the C-tail, suggesting the presence of at least two distinct signaling mechanisms utilized by Cx43 to affect motility. Finally, we used time-lapse imaging to examine the behavior of migrating cells and it was apparent that the C-tail was associated with a lamellipodia-based migration not observed in either mock or TrCx43 expressing LN18 cells. Our study shows for the first time that a free C-tail is sufficient to induce Cx43-dependent changes in cell morphology and that Cx43 signaling is linked to the regulation of the actin cytoskeleton.
Crespin
Sophie
S
Institut de Physiologie et Biologie Cellulaires, Université de Poitiers, CNRS-UMR 6187, 40 Avenue du Recteur Pineau, 86022 Poitiers Cedex, France.
Bechberger
John
J
Mesnil
Marc
M
Naus
Christian C
CC
Sin
Wun-Chey
WC
D015153:Blotting, Western; D002450:Cell Communication / Q000502:physiology*; D045744:Cell Line, Tumor; D018031:Connexin 43 / Q000737:chemistry / Q000378:metabolism*; D003599:Cytoskeleton / Q000502:physiology*; D017629:Gap Junctions / Q000737:chemistry / Q000378:metabolism; D005910:Glioma; D006801:Humans; D007150:Immunohistochemistry; D015398:Signal Transduction / Q000502:physiology*; D014161:Transduction, Genetic
D018031:Connexin 43; C500216:GJA1 protein, human