The Instrumentation Core will provide all projects and principle investigators of this Program Project Grant with: a) confocal and conventional light microscopy and image analyses of fixed samples for localization and colocalization experiments, as well as quantification of morphological changes. b) ratiometric fluorescence microscopy of live cells for dynamic measurements of intracellular ion concentration of membrane potential changes. c) microinjection of proteins and nucleic acids to modulate intracellular message or signaling systems. d) injection of proteins into cells by electroporation to effect modulation of intracellular signaling system in biochemical studies. e) routine resistance and potential measurements of epithelial monolayers as quality control. f) quantitative analyses of protein and nucleic aid gels and immuno-blots. The staff of the Core will carry out measurements and provide assistance and counseling in planning of measurements and data analyses.