Intercellular communication via gap junction channels

Hülser, Dieter F.; Eckert, Reiner; Irmer, Uwe; Kriščiukaitis, Algimantas; Mindermann, Anja; Pleiss, Jürgen; Rehkopf, Beate; Sharovskaya, Julia; Traub, Otto

doi:10.1016/s0302-4598(98)00076-2

Cited by 7 publications

(1 citation statement)

References 36 publications

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“…However, by analysing subcellular fractions of this truncated protein it was obvious that still 25% of this connexin was found in the plasma membranes [15]. HeLa wtCx43 transfectants are well coupled, both electrically and after dye injection [10,12,16]; they form permeable junctions also after heterotypic coupling with wtCx45 transfectants [12]. Here we demonstrate that this partial truncation of the COOH terminus has no influence on channel assembly and plaque formation but leads to damage of essential regulatory sites forthe opening and closing of these channels.…”

Section: Introductionmentioning

confidence: 99%

Functional rescue of defective mutant connexons by pairing with wild-type connexons

Hülser

Rütz

Eckert

et al. 2001

Pfl�gers Archiv European Journal of Physiology

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We have compared the functional and structural integrity of gap junction channels assembled from a Cx45 truncation mutant with those of gap junction channels assembled from wild-type (wt) Cx45 and Cx43. These channel-forming proteins are constitutively expressed in HeLa cells. The truncation mutant lacks the last 26 amino acids of the COOH-terminus, including nine serine phosphorylation sites that are associated with regulatory processes of these channels. We determined the presence of gap junction plaques in these cells with the immunogold freeze fracture technique, which showed that plaque formation is similar in all the clones investigated. Junctional permeability was probed with calcein transfer and flow cytometry analyses and junctional conductance was measured in cell pairs with double whole-cell patch-clamp techniques. For homotypic pairing only the truncated mutant did not form permeable channels. However, coupling was restored for heterotypic channels (pairing wtCx45- or wtCx43- with mutant-connexons), whose junctional communication was not different from that of the homotypic channels. Our results indicate that the presence of gap junction plaques does not warrant functional coupling and that heterotypic trCx45/wtCx45 channels can be regulated by the intact wtCx45 connexons. This dominant-positive effect is also operative when wtCx43 are paired with trCx45 connexons.

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