Hormone release from a kidney cell, STORM and TIRFM

Super-resolution micrograph of part of the plasma membrane in a rat kidney cell. The cell is from an adrenal medulla tumour cell line (phaeochromocytoma). One way cells communicate with each other is to release hormones into the bloodstream. In this image, hormone (green; GFP labelled neuropeptide Y) inside small membrane sacs (vesicles) are visible at the plasma membrane, ready to be released. Clustered around these vesicles are lots of individual proteins (purple; syntaxin 1a) required for this process. These proteins are only a few nanometres in size (a billionth of a metre) which are as tiny to us as Jupiter is large. Width of image is 3 micrometres. Single molecule localisation microscopy (specifically stochastic optical reconstruction microscopy or STORM, combined with total internal reflection fluorescence microscopy, TIRFM) is one type of super-resolution microscopy.