In this study, we examine the role of the gap junction protein, connexin43 (Cx43), in the transcriptional response of osteocalcin to fibroblast growth factor 2 (FGF2) in MC3T3 osteoblasts. By luciferase reporter assays, we identify that the osteocalcin transcriptional response to FGF2 is markedly increased by overexpression of Cx43, an effect that is mediated by Runx2 via its OSE2 cognate eleme...

OBJECTIVE To investigate correlations among A-kinase anchor protein95 (AKAP95), Connexin43 (Cx43), CyclinE1 and CyclinD1 in esophageal squamous cell cancer tissues, and their relationship with clinical and pathological parameters. METHODS The protein levels of AKAP95, Cx43, CyclinE1 and CyclinD1 in 54 cases of esophageal squamous cell cancer tissues were determined by immunohistochemistry. ...

Embryonic stem (ES) cells and embryonal carcinoma (EC) cells express high amounts of functional connexin43 (Cx43). During mesoderm formation and subsequent cardiac differentiation, Cx43 is initially down-regulated but is up-regulated again as the emerging cardiomyocytes mature. In this study, we investigated the regulation of Cx43 expression during early phases of differentiation in F9 and P19 ...

AIMS Hearts of mice expressing K258stop in place of connexin43 (Cx43) protein were subjected to acute myocardial infarction in order to assess the importance of Cx43 regulation on infarct size and arrhythmia susceptibility. This mutation K258stop prevents chemical regulation of Cx43 channels, including by low intracellular pH. METHODS AND RESULTS Langendorff-perfused hearts of mice harbouring...

The distribution of Connexin43 (Cx43) was examined by immunoblotting and immunofluorescence microscopy in the retinas of five different vertebrates by using a C-terminal specific peptide antibody. The specificity of the antibody was proved on immunoblots, in which it showed cross reactivity with a 43-kDa protein in rat heart homogenates as well as in homogenates of rabbit, rat, chicken, turtle,...

Hyperhomocysteinemia is an established cause of defective vasorelaxation. Gene expression screening of human umbilical vein endothelial cells (HUVEC) treated with homocysteine (Hcy) revealed that connexin43 (Cx43) was upregulated. Expression of Cx43 was increased more than twofold in Hcy-treated HUVEC. Gap junctional communication (Lucifer yellow and whole cell patch clamp) was not enhanced in ...

AIMS We have shown that failing human and rabbit left ventricle (LV) exhibits downregulation and dephosphorylation of connexin43 (Cx43) and that Cx43 dephosphorylation in heart failure (HF) contributes to reduced cell coupling. However, the role of Cx43 downregulation per se in impaired coupling in HF is unclear. METHODS AND RESULTS First, we used adenovirus (Ad) encoding a Cx43 siRNA sequenc...

Protein kinases have long been reported to regulate connexins; however, little is known about the involvement of phosphatases in the modulation of intercellular communication through gap junctions and the subsequent downstream effects on cellular processes. Here, we identify an interaction between the T-cell protein tyrosine phosphatase (TC-PTP, officially known as PTPN2) and the carboxyl termi...

Treatment of WB-F344 rat liver epithelial cells with DDT (1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane) or lindane induces a loss of gap junction plaques and a decrease in the phosphorylated gap junction protein connexin43-P2 (Cx43-P2), which is associated with the plaques. In this study we have considered several mechanisms. The loss of junctional plaques could be due to disaggregation of jun...

Knockout mice deficient in the gap junction gene connexin43 exhibit developmental anomalies associated with abnormal neural crest, primordial germ cell, and proepicardial cell migration. These migration defects are due to a loss of directional cell movement, and are associated with abnormal actin stress fiber organization and a loss of polarized cell morphology. To elucidate the mechanism by wh...