The intracellular Ca 2؉ receptor calmodulin (CaM) coordinates responses to extracellular stimuli by modulating the activities of its various binding proteins. Recent reports suggest that, in addition to its familiar functions in the cytoplasm, CaM may be directly involved in rapid signaling between cytoplasm and nucleus. Here we show that Ca

Many stimuli increase cytoplasmic Ca2+ concentrations as an early signal transduction event and alter the patterns of nuclear gene transcription, but the mechanisms by which Ca2+ signals are transduced to the nucleus are not known. This article shows that at least four DNA binding proteins from cauliflower nuclear extracts are also calmodulin (CaM) binding proteins. CaM enhances the binding of these proteins to a C/G-box sequence element in the Arabidopsis Cam-3 promoter. Binding to the C/G-box is enhanced preferentially by the CaM isoform encoded by Cam-3. However, it is not clear whether the effect is mediated directly by CaM or indirectly through the activity of a CaM-regulated protein phosphatase. CaM also binds recombinant TGA3 and enhances its binding to the same Cam-3 promoter element. These results are consistent with the idea that a Ca(2+)-mediated signalling pathway eliciting some changes in gene expression may consist of CaM, or a structurally related Ca2+ binding protein, and transcription factors.

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Background: NCI60 cell lines are derived from cancers of 9 tissue origins and have been invaluable in vitro models for cancer research and anti-cancer drug screen. Although extensive studies have been carried out to assess the molecular features of NCI60 cell lines related to cancer and their sensitivities to more than 100,000 chemical compounds, it remains unclear if and how well these cell lines represent or model their tumor tissues of origin. Identification and confirmation of correct origins of NCI60 cell lines are critical to their usage as model systems and to translate in vitro studies into clinical potentials. Here we report a direct comparison between NCI60 cell lines and primary tumors by analyzing global gene expression profiles.