Visualization of in vivo protein levels and localization is essential to analysis and elucidation of Hippo signaling mechanisms and its roles in diverse tissues. This is best done by imaging proteins using fluorescent labels. Fluorescent labeling of a protein can be achieved by direct conjugation to an intrinsically fluorescent protein, like GFP, or by use of antibodies conjugated to fluorescent dyes. Immunofluorescence imaging in Drosophila typically begins with dissection and fixation of a sample tissue, followed by a series of washes and incubations with primary antibodies, directed against proteins of interest, and dye-labeled secondary antibodies, directed against the primary antibodies. This may be followed by fluorescent dyes that label cellular components, such as DNA-labeling dyes to mark nuclei. After staining and washing is completed, samples are placed in a mounting media, transferred to a microscope slide, and imaged on a confocal microscope.