FluoQ: a tool for rapid analysis of multiparameter fluorescence imaging data applied to oscillatory events.
Stein, F., Kress, M., Reither, S., Piljic, A. & Schultz, C.
ACS Chem Biol. 2013 Sep 20;8(9):1862-8. doi: 10.1021/cb4003442. Epub 2013 Aug 6.
The number of fluorescent sensors and their use in living cells has significantly increased in the past years. Yet, the analysis of data from single cells or cell populations usually remains a very time-consuming enterprise. Here, we introduce FluoQ, a new macro for the image analysis software ImageJ, which enables fast analysis of multiparameter time-lapse fluorescence microscopy data with minimal manual input. FluoQ provides statistical analysis of all measured parameters and delivers the results in multiple graphic and numeric displays. We demonstrate the power of FluoQ by applying the macro to data analysis in the development and optimization of novel FRET reporters for monitoring the performance of calcium/calmodulin-binding inositol trisphosphate kinases A and B (ITPKA and ITPKB) in HeLa cells. We find that conformational changes in the ITPKA-based sensor follow receptor-mediated calcium oscillations. This indicates that ITPKA contributes to the regulation of intracellular calcium transients by limiting inositol trisphosphate levels.
The fatty acid composition of diacylglycerols determines local signaling patterns.
Nadler, A., Reither, G., Feng, S., Stein, F., Reither, S., Muller, R. & Schultz, C.
Angew Chem Int Ed Engl. 2013 Jun 10;52(24):6330-4. doi: 10.1002/anie.201301716.Epub 2013 May 29. Europe PMC
In vivo profiling and visualization of cellular protein-lipid interactions using bifunctional fatty acids.
Haberkant, P., Raijmakers, R., Wildwater, M., Sachsenheimer, T., Brugger, B., Maeda, K., Houweling, M., Gavin, A.C., Schultz, C., van Meer, G., Heck, A.J. & Holthuis, J.C.
Angew Chem Int Ed Engl. 2013 Apr 2;52(14):4033-8. doi: 10.1002/anie.201210178.Epub 2013 Feb 28. Europe PMC
Spatiotemporal control of endocytosis by phosphatidylinositol-3,4-bisphosphate.
Posor, Y., Eichhorn-Gruenig, M., Puchkov, D., Schoneberg, J., Ullrich, A., Lampe, A., Muller, R., Zarbakhsh, S., Gulluni, F., Hirsch, E., Krauss, M., Schultz, C., Schmoranzer, J., Noe, F. & Haucke, V.
Nature. 2013 Jul 11;499(7457):233-7. doi: 10.1038/nature12360. Epub 2013 Jul 3.
Phosphoinositides serve crucial roles in cell physiology, ranging from cell signalling to membrane traffic. Among the seven eukaryotic phosphoinositides the best studied species is phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2), which is concentrated at the plasma membrane where, among other functions, it is required for the nucleation of endocytic clathrin-coated pits. No phosphatidylinositol other than PI(4,5)P2 has been implicated in clathrin-mediated endocytosis, whereas the subsequent endosomal stages of the endocytic pathway are dominated by phosphatidylinositol-3-phosphates(PI(3)P). How phosphatidylinositol conversion from PI(4,5)P2-positive endocytic intermediates to PI(3)P-containing endosomes is achieved is unclear. Here we show that formation of phosphatidylinositol-3,4-bisphosphate (PI(3,4)P2) by class II phosphatidylinositol-3-kinase C2alpha (PI(3)K C2alpha) spatiotemporally controls clathrin-mediated endocytosis. Depletion of PI(3,4)P2 or PI(3)K C2alpha impairs the maturation of late-stage clathrin-coated pits before fission. Timed formation of PI(3,4)P2 by PI(3)K C2alpha is required for selective enrichment of the BAR domain protein SNX9 at late-stage endocytic intermediates. These findings provide a mechanistic framework for the role of PI(3,4)P2 in endocytosis and unravel a novel discrete function of PI(3,4)P2 in a central cell physiological process.