Photo-Activated Localization Microscopy (PALM) is Nobel Prize awarded super resolution microscopy technique which provides images with a resolution beyond the diffraction limit of conventional light microscopes (ca. 200 nm). It provides a view on the events happening on the organellar level. If you want to observe the events on the nm scale this is one of the options.
In PALM, observed cells express the target protein fused to photoactivatable fluorescent proteins which can switch between dark and bright states upon laser irradiation. Superior features of PALM (up) when compared to confocal microscopy (down) are shown here, visualizing the localization of two reporter proteins in the yeast plasma membrane, homogenously distributed Gap1C-mEos3.2 (left) and Sur7-mEos3.2 localized to MCC membrane microdomains (right). Scale bar 1000nm.