 | Figure 1
Nature Cell Biology
6, 1129 - 1134 (2004)
Published online: 24 October 2004; | doi:10.1038/ncb1188
Nitric oxide induces coupling of mitochondrial signalling with the endoplasmic reticulum stress responseWeiming Xu, Lizhi Liu, Ian G. Charles
& Salvador Moncada | | | | Figure 1. NO increases expression of Grp78 and cleavage of p90 ATF6.
(a) Northern blot analysis of Grp78 and iNOS mRNA in the non-NO-generating parental cell lines T-REx-293 and EcR-293, and in their respective NO-generating derived cell lines Tex293 clone-22 and EcR293 clone-11 subclone-1 after treatment with tetracycline (10 ng ml-1) or with muristerone A (5 and 10  M).  -actin was used as an internal control (n = 3). (b) Western blot analysis of Grp78 protein from untreated (None), muristerone A (10 M, 16h; MuA)-treated, muristerone A plus ODQ (10 M)-treated and muristerone A plus L-NIO (20 M)-treated EcR293 clone-11 subclone-1 cells.  -tubulin was used as a control (n = 3). Scanning densitometry of six western blots is shown below. Asterisk indicates a significant difference (P < 0.05) from non-NO-generating cells. (c) Western blot analysis of Grp78 protein in T-REx-293 cells at different times after treatment with the NO donor DETA-NONOate (500 M). Scanning densitometry of three western blots is shown below. Asterisk indicates a significant difference (P < 0.05) from untreated cells. (d) Cleavage of p90 ATF6 in Tex293 clone-22 cells. Treatment with tetracycline significantly increased the amount of soluble transcription factor p50 ATF6 and reduced the amount of uncleaved protein p90 ATF6 (whole-cell extracts). Pre-treatment of tetracycline-treated cells with the NOS inhibitor L-NIO (20 M) attenuated the increase in p50 ATF6. Scanning densitometry of three western blots is shown below. Data are presented as the percentage conversion to p50, calculated as the p50 value divided by the sum of p50 + p90, divided by the tubulin value, multiplied by 100 (that is, p50/(p50 + p90)/tubulin,  100). Asterisk indicates a significant difference (P < 0.05) from untreated cells; double asterisk indicates a significant difference (P < 0.05) from NO-generating cells in the absence of L-NIO.
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