Gap-junctional communication in a communication-defective and in a communication-competent teratocarcinoma cell line

1985 ◽  
Vol 76 (1) ◽  
pp. 85-95
Author(s):  
C.W. Lo ◽  
D. Fang ◽  
M.L. Hooper
Keyword(s):  
Cell Line ◽  
Coupling Coefficient ◽  
Dye Coupling ◽  
Cell Coupling ◽  
Teratocarcinoma Cell ◽  
Gap Junctional Communication ◽  
Junctional Communication ◽  
Gap Junctional ◽  
Ionic Coupling ◽  
Cell Cell

We examined the gap-junctional communication properties of a communication-defective cell line R5/3 and its communication-competent revertant H2T12. For these studies, we carried out microelectrode impalements to monitor ionic coupling and dye coupling. Our dye-injection experiments revealed that the H2T12 cells are much more efficient in dye coupling than the R5/3 cells. This latter observation is in agreement with the previous finding that the H2T12 cells are much better metabolically coupled than the R5/3 cells. With ionic coupling measurements, however, both cell lines exhibited similar levels of cell-cell coupling. The R5/3 cells demonstrated an ionic coupling coefficient of 0.19 +/− 0.011 (S.E.M.) and H2T12 a coupling coefficient of 0.25 +/− 0.009 (S.E.M.). These results in conjunction with observations from other studies indicate that the different experimental approaches for monitoring gap-junctional communication may have different levels of sensitivity for detecting as opposed to measuring the level of cell-cell coupling.

scholarly journals Gap junctional communication in the extraembryonic tissues of the gastrulating mouse embryo.

1989 ◽  
Vol 109 (6) ◽  
pp. 3015-3026 ◽  
Author(s):  
G H Kalimi ◽  
C W Lo
Keyword(s):  
Mouse Embryo ◽  
Lucifer Yellow ◽  
Dye Coupling ◽  
Gap Junctional Communication ◽  
Stage Of Development ◽  
Junctional Communication ◽  
Gap Junctional ◽  
Ectoplacental Cone ◽  
Ionic Coupling ◽  
Extraembryonic Tissues

We characterized gap junctional communication in the extraembryonic tissues of the 7.5-d gastrulating mouse embryo. At this stage of development, the extraembryonic tissues form a large part of the conceptus, and link the embryo proper to the maternal tissue. Using Lucifer yellow injections, cells in most extraembryonic tissues were observed to be very well dye coupled, the only exception being the peripheral regions of the ectoplacental cone. Of particular interest was the fact that no dye coupling was detected between the three major extraembryonic tissues. Thus, the extraembryonic ectoderm (EEC), the extraembryonic endoderm (EEN), and the ectoplacental cone (EPC) corresponded to separate communication compartments, with the EPC being further subdivided into three compartments. Interestingly, the EEN was observed to exhibit a very low level of dye coupling with the adjacent visceral embryonic endoderm (EN), and consistent with the latter dye coupling results was the finding that the EEN was ionically coupled to the EN, but not with any other extraembryonic tissues. However, in the EPC, ionic coupling studies show that the central region was well coupled ionically to the EEC, but only weakly coupled to the peripheral EPC. These findings, in conjunction with our previous study (1988. J. Cell Biol. 107:241-255), demonstrate that the 7.5-d mouse conceptus is subdivided into at least nine major Lucifer yellow-delineated communication compartments, with ionic coupling across some of these compartments effectively unifying the embryo into two large domains corresponding to the embryo proper and the major extraembryonic tissues.

scholarly journals Differential phosphorylation of the gap junction protein connexin43 in junctional communication-competent and -deficient cell lines.

1990 ◽  
Vol 111 (5) ◽  
pp. 2077-2088 ◽  
Author(s):  
L S Musil ◽  
B A Cunningham ◽  
G M Edelman ◽  
D A Goodenough
Keyword(s):  
Cell Adhesion ◽  
Gap Junctions ◽  
Gap Junction ◽  
Cell Lines ◽  
Gap Junctional Communication ◽  
Competent Cells ◽  
Deficient Cell ◽  
Junctional Communication ◽  
Gap Junctional ◽  
Cell Cell

Connexin43 is a member of the highly homologous connexin family of gap junction proteins. We have studied how connexin monomers are assembled into functional gap junction plaques by examining the biosynthesis of connexin43 in cell types that differ greatly in their ability to form functional gap junctions. Using a combination of metabolic radiolabeling and immunoprecipitation, we have shown that connexin43 is synthesized in gap junctional communication-competent cells as a 42-kD protein that is efficiently converted to a approximately 46-kD species (connexin43-P2) by the posttranslational addition of phosphate. Surprisingly, certain cell lines severely deficient in gap junctional communication and known cell-cell adhesion molecules (S180 and L929 cells) also expressed 42-kD connexin43. Connexin43 in these communication-deficient cell lines was not, however, phosphorylated to the P2 form. Conversion of S180 cells to a communication-competent phenotype by transfection with a cDNA encoding the cell-cell adhesion molecule L-CAM induced phosphorylation of connexin43 to the P2 form; conversely, blocking junctional communication in ordinarily communication-competent cells inhibited connexin43-P2 formation. Immunohistochemical localization studies indicated that only communication-competent cells accumulated connexin43 in visible gap junction plaques. Together, these results establish a strong correlation between the ability of cells to process connexin43 to the P2 form and to produce functional gap junctions. Connexin43 phosphorylation may therefore play a functional role in gap junction assembly and/or activity.

scholarly journals Asymmetric patterns of gap junctional communication in developing chicken skin

Development ◽  
1993 ◽  
Vol 119 (1) ◽  
pp. 85-96 ◽  
Author(s):  
F. Serras ◽  
S. Fraser ◽  
C.M. Chuong
Keyword(s):  
Lucifer Yellow ◽  
Single Cells ◽  
Dye Coupling ◽  
Dye Transfer ◽  
Gap Junctional Communication ◽  
Junctional Communication ◽  
Chicken Skin ◽  
Preferential Pathways ◽  
Gap Junctional ◽  
Feather Development

To study the pattern of gap junctional communication in chicken skin and feather development, we injected Lucifer Yellow into single cells and monitored the transfer of the fluorescent dye through gap junctions. Dye coupling is present between cells of the epithelium as well as between cells of the mesoderm. However, dye transfer did not occur equally in all directions and showed several consistent patterns and asymmetries, including: (1) no dye coupling between mesoderm and epithelium, (2) partial restriction of dye coupling at the feather bud/interbud boundary during early feather bud development, (3) preferential distribution of Lucifer Yellow along the anteroposterior axis of the feather placode and (4) absence of dye coupling in some epithelial cells. These results suggest the presence of preferential pathways of communication that may play a role in the patterning of chicken skin.

VEGF transiently disrupts gap junctional communication in endothelial cells

2001 ◽  
Vol 114 (6) ◽  
pp. 1229-1235
Author(s):  
S. Suarez ◽  
K. Ballmer-Hofer
Keyword(s):  
Endothelial Cells ◽  
Growth Factor ◽  
Tyrosine Kinase ◽  
Map Kinases ◽  
Cell Junctions ◽  
Early Effect ◽  
Gap Junctional Communication ◽  
Junctional Communication ◽  
Gap Junctional ◽  
Cell Cell

Vascular endothelial growth factor, VEGF, stimulates angiogenesis by directly acting on endothelial cells. The effects of VEGF are mediated by two tyrosine kinase receptors, VEGFR-1 (Flt-1) and VEGFR-2 (Flk-1/KDR) that are highly related to receptors of the platelet derived growth factor (PDGF) receptor family. We are interested in early signalling events downstream from VEGF receptors that affect blood vessel homeostasis. Endothelial cells form multiple types of cell-cell junctions that are required for cellular organization into complex networks. These junctions also regulate communication among adjacent cells. Stimulation by various growth factors such as epidermal growth factor (EGF) or PDGF has been shown to disrupt cell-cell junctions, consequently affecting cell-to-cell communication. We investigated gap junctional communication (GJC) by monitoring the transfer of a low molecular mass fluorescent tracer molecule between adjacent cells using immunofluorescence microscopy. VEGF maximally blocked GJC 15 minutes after growth factor administration. The cells resumed communication via gap junctions within 1–2 hours after treatment. This early effect of VEGF on communication correlated with changes in the phosphorylation state of one of the proteins involved in gap junction formation, connexin 43 (Cx43). The signalling mechanisms involved in this phenomenon depend on activation of VEGFR-2, impinge on a tyrosine kinase of the Src family and activate the Erk family of MAP kinases. The function of VEGF-mediated disruption of GJC might be to restrict an increase in endothelium permeability to the environment affected by local injury to blood vessels.

scholarly journals Regulation of connexin43 gap junctional communication by phosphatidylinositol 4,5-bisphosphate

2007 ◽  
Vol 177 (5) ◽  
pp. 881-891 ◽  
Author(s):  
Leonie van Zeijl ◽  
Bas Ponsioen ◽  
Ben N.G. Giepmans ◽  
Aafke Ariaens ◽  
Friso R. Postma ◽  
...  
Keyword(s):  
Second Messengers ◽  
Pdz Domain ◽  
Cell Communication ◽  
Receptor Activation ◽  
Gap Junctional Communication ◽  
Signaling Complex ◽  
Junctional Communication ◽  
Gap Junctional ◽  
Zona Occludens ◽  
Cell Cell

Cell–cell communication through connexin43 (Cx43)-based gap junction channels is rapidly inhibited upon activation of various G protein–coupled receptors; however, the mechanism is unknown. We show that Cx43-based cell–cell communication is inhibited by depletion of phosphatidylinositol 4,5-bisphosphate (PtdIns[4,5]P2) from the plasma membrane. Knockdown of phospholipase Cβ3 (PLCβ3) inhibits PtdIns(4,5)P2 hydrolysis and keeps Cx43 channels open after receptor activation. Using a translocatable 5-phosphatase, we show that PtdIns(4,5)P2 depletion is sufficient to close Cx43 channels. When PtdIns(4,5)P2 is overproduced by PtdIns(4)P 5-kinase, Cx43 channel closure is impaired. We find that the Cx43 binding partner zona occludens 1 (ZO-1) interacts with PLCβ3 via its third PDZ domain. ZO-1 is essential for PtdIns(4,5)P2-hydrolyzing receptors to inhibit cell–cell communication, but not for receptor–PLC coupling. Our results show that PtdIns(4,5)P2 is a key regulator of Cx43 channel function, with no role for other second messengers, and suggest that ZO-1 assembles PLCβ3 and Cx43 into a signaling complex to allow regulation of cell–cell communication by localized changes in PtdIns(4,5)P2.

Decreased gap-junctional communication associated with segregation of the neuronal phenotype in the RT4 cell-line family

1998 ◽  
Vol 292 (1) ◽  
pp. 27-35 ◽  
Author(s):  
L. M. Donahue ◽  
Daniel R. Webster ◽  
Ivvanee Martinez ◽  
David C. Spray
Keyword(s):  
Cell Line ◽  
Neuronal Phenotype ◽  
Gap Junctional Communication ◽  
Junctional Communication ◽  
Gap Junctional

scholarly journals Inhibition of Endothelial Wound Repair by Dominant Negative Connexin Inhibitors

2001 ◽  
Vol 12 (4) ◽  
pp. 831-845 ◽  
Author(s):  
Brenda R. Kwak ◽  
Michael S. Pepper ◽  
Daniel B. Gros ◽  
Paolo Meda
Keyword(s):  
Endothelial Cells ◽  
Wound Repair ◽  
Single Cells ◽  
Dominant Negative ◽  
Cell Coupling ◽  
Mechanical Wounding ◽  
Functional Changes ◽  
Gap Junctional Communication ◽  
Junctional Communication ◽  
Gap Junctional

Wounding of endothelial cells is associated with altered direct intercellular communication. To determine whether gap junctional communication participates to the wound repair process, we have compared connexin (Cx) expression, cell-to-cell coupling and kinetics of wound repair in monolayer cultures of PymT-transformed mouse endothelial cells (clone bEnd.3) and in bEnd.3 cells expressing different dominant negative Cx inhibitors. In parental bEnd.3 cells, mechanical wounding increased expression of Cx43 and decreased expression of Cx37 at the site of injury, whereas Cx40 expression was unaffected. These wound-induced changes in Cx expression were associated with functional changes in cell-to-cell coupling, as assessed with different fluorescent tracers. Stable transfection with cDNAs encoding for the chimeric connexin 3243H7 or the fusion protein Cx43-βGal resulted in perturbed gap junctional communication between bEnd.3 cells under both basal and wounded conditions. The time required for complete repair of a defined wound within a confluent monolayer was increased by ∼50% in cells expressing the dominant negative Cx inhibitors, whereas other cell properties, such as proliferation rate, migration of single cells, cyst formation and extracellular proteolytic activity, were unaltered. These findings demonstrate that proper Cx expression is required for coordinated migration during repair of an endothelial wound.

Gap junctional communication underpins EDHF-type relaxations evoked by ACh in the rat hepatic artery

2001 ◽  
Vol 280 (6) ◽  
pp. H2441-H2450 ◽  
Author(s):  
Andrew T. Chaytor ◽  
Patricia E. M. Martin ◽  
David H. Edwards ◽  
Tudor M. Griffith
Keyword(s):  
Gap Junctions ◽  
Hepatic Artery ◽  
Lucifer Yellow ◽  
Dye Transfer ◽  
Cell Coupling ◽  
Gap Junctional Communication ◽  
Junctional Communication ◽  
A7r5 Cells ◽  
Gap Junctional

Synthetic peptides homologous to the Gap 26 and Gap 27 domains of the first and second extracellular loops of the major vascular connexins (Cx37, Cx40, and Cx43) have been used to investigate the role of gap junctions in endothelium-derived hyperpolarizing factor (EDHF)-type relaxations of the rat hepatic artery. These peptides were designated 37,40Gap 26,43Gap 26, 37,43Gap 27, and 40Gap 27, according to connexin specificity. When administered at 600 μM, none of the peptides individually affected maximal EDHF-type relaxations to ACh. By contrast, at 300 μM each, paired peptide combinations targeting more than one connexin subtype attenuated relaxation by up to 50%, and responses were abolished by the triple peptide combination 43Gap 26 + 40Gap 27 + 37,43Gap 27. In parallel experiments with A7r5 cells expressing Cx40 and Cx43, neither 43Gap 26 nor40Gap 27 affected intercellular diffusion of Lucifer yellow individually but, in combination, significantly attenuated dye transfer. The findings confirm that functional cell-cell coupling may depend on more than one connexin subtype and demonstrate that direct intercellular communication via gap junctions constructed from Cx37, Cx40, and Cx43 underpins EDHF-type responses in the rat hepatic artery.

Sign in / Sign up

Export Citation Format

Share Document