Confocal imaging optically reduces signals from the out-of-focus plane, thereby improving image contrast and resolution. The Leica SP2 system consists of a Leica inverted microscope equipped with motorized z-stage and multiple laser lights, which allows optical sectioning of multiply labeled fixed and live cells. Four laser sources cover essentially the entire range of visible light spectrum, including Diode Violet/Blue laser (405nm), Ar (458, 476, 488, 514 nm), Yellow DPSS (561 nm) and HeNe (633nm). Any dye or fluorophore that is excited by one of these wavelengths can be used.  Using unique prizm-based light separation and spectral unmixing, SP2 allows fine-tuning of the range for collecting emission light, thus permitting image acquisition of a variety of dyes.  It also offers tools for fluorsecence recovery after photobleaching (FRAP) and fluorescence resonance energy transfer (FRET) to study dynamics of macromolecules and organelles and a various programs for analyzing images including simple 3D construction and quantification.  The inverted microscope allows use of the open cell culture chamber (Harvard Apparatus PDMI-2) and microinjection and micromanipulation systems for drug treatment and cell manipulation during live cell imaging.