Previous studies have indicated that phosphorylation of Cx43 by c Src reduces gap junc tional selleck catalog communication depending on the interaction be tween Cx43CT and c Src. Interestingly, recent studies have suggested that the interaction between Cx43 and c Src reciprocally modulates their activities. The level of Cx43 expression is important in regulating c Src activ ity. Upregulation of Cx43 in glioma cells reduces c Src ac tivity while silencing of Cx43 activates c Src in astrocytes. In our study, reduction of Cx43 protein level in duced by high glucose was accompanied by decrease in the amount of c Src interacting with Cx43, thereby in creasing the activity of c Src in the cytoplasm. This finding indicates that downregulation of Cx43 by high glucose ac tivates c Src.

The molecular mechanism by which Inhibitors,Modulators,Libraries c Src regulates NF B has been suggested to be dependent on the in teraction between c Src and IB kinase B or IB. IKKB is phosphorylated by c Src, which is involved in TNF induced ICAM 1 expression. Tyrosine phosphorylation of IB activates NF B through a redox regulated and c Src dependent mechanism follow ing hypoxiareoxygenation. In the current study, IB was found to interact with c Src after exposure of GMCs to high glucose for 15 min, and to be accompan ied by tyrosine phosphorylation of IB, persisting for at least 120 min. We Inhibitors,Modulators,Libraries have previously shown that NF B p65 is translocated into the nucleus after exposure of GMCs to high glucose levels for 30 min.

Interest ingly, IKK mediated serine phosphorylation Inhibitors,Modulators,Libraries of IB, a classic pathway of NF B activation, was detected after exposure of GMCs to high glucose levels for 90 min, and this was accompanied by degradation of IB, which occurs after NF B p65 nuclear translocation. Thus, tyrosine phosphorylation of IB could possibly play an important role in the initial step of high glucose induced NF B p65 activation. As described in a previ ous study, tyrosine phosphorylation activates Inhibitors,Modulators,Libraries NF B without degradation of IB. We did not observe degradation of IB when NF B p65 was translocated into the nucleus at early stages of exposure of GMCs to high glucose. Immunofluorescence images showed that Cx43 and c Src were co localized around the cell membrane in GMCs maintained in normal glucose. There was no interaction between c Src and IB in GMCs cultured in normal glucose.

However, co localization of c Src and IB was observed in the cytoplasm after exposure of GMCs to high glucose for 30 min. Based on these data, we propose that decrease in Cx43 expression enhances the activity of c Src Inhibitors,Modulators,Libraries by acting as a substrate of the kin ase, useful site which promotes interaction between c Src and IB and leads to NF B activation. The results of our study confirm that PP2, an inhibitor of c Src, can inhibit the tyrosine phosphorylation of IB and translocation of NF B p65 into the nucleus, which suggests that c Src regulates NF B by inducing tyrosine phosphorylation of IB.