Rabbit Anti-Human JUND (Phospho-Ser255) polyclonal antibody

Previously, we identified an arylstibonic acid, NSC13778 that specifically binds to the basic region of the C/EBP alpha B-ZIP domain and disrupts DNA binding. We now examine a panel of 14 additional arylstibonic acid derivatives of NSC13778 for their ability to inhibit the DNA binding of five B-ZIP dimers (c-Fos vertical bar JunD, VBP, C/EBR alpha, C/EBP beta, and CREB). They show various specificities at inhibiting the DNA binding of five B-ZIP domains. NSC13746 inhibits the DNA binding of C/EBP beta and CREB at 100 nM and promiscuously inhibiting the DNA binding of all five proteins in the 1 mu M range. Dialysis experiments indicate that NSC 13746 binding to the B-ZIP domain is reversible. Thermal denaturation studies indicate that NSC13746 binds the B-ZIP domain. Some compounds specifically inhibit DNA binding, with VBP and c-Fos vertical bar JunD being most easily disrupted. These compounds inhibit, with similar specificities to the pure B-ZIP domains, the DNA binding of nuclear extract to the AP1 DNA sequence but no inhibition is observed to SP1 containing oligonucleotide. Transient transfection assays indicate that NSC13746 can inhibit the TPA induced activation of two B-ZIP dependent reporters. These experiments suggest that arylstibonic acids are promising leads for inhibiting the DNA binding of a group of B-ZIP proteins in cells. Published by Elsevier Inc.

CD2-associated protein (CD2AP) plays a critical role in the maintenance of the kidney filtration barrier. In this study, we showed that epidermal growth factor (EGF) led to an increase of the CD2AP protein and mRNA in the human renal proximal tubular epithelial cell line HK-2 cells, which was due to the elevation of CD2AP promoter activity. Upon deletion and mutation analysis, electrophoretic mobility shift assays and chromatin immunoprecipitation, an AP-1-like element within CD2AP promoter was characterized, by which EGF recruited c-fos and JunD, two components of AP-1, to the human CD2AP gene promoter and suppressed angiotensin II-induced apoptosis in HK-2 cells. Specific siRNA was synthesized to knock down the human CD2AP gene in HK-2 cells. We found that CD2AP deficiency attenuated the inhibitory effects of EGF and predisposed the renal tubular epithelial cells to undergo angiotensin If-induced apoptosis. Furthermore, EGF-induced increases of CD2AP protein and mRNA expressions in HK-2 cells were significantly inhibited by the transfection of dominant negative JunD or c-fos vector, which was in parallel with a marked reduction of antiapoptotic effect of EGF. These results indicated that the antiapoptotic effect of ECF/CD2AP signal transduction was mediated by JunD and c-fos, at least partially. This study defined a new EGF/AP-1/CD2AP mediated cell-survival signaling, which might be useful to clarify the molecular mechanisms responsible for CD2AP associated kidney diseases. (C) 2008 Elsevier B.V. All rights reserved.