Switchable fluorophores for protein labeling in living cells

Numerous synthetic fluorophores have been developed that can switch their spectroscopic properties upon interaction with other molecules or by irradiation with light. In recent years, protein-labeling techniques have been introduced that permit the specific attachment of such molecules to proteins of interest in living cells. We review here how the attachment of switchable fluorophores to selected proteins of interest via self-labeling protein tags enables new applications in different areas of biology and discuss how these molecules could be further improved.

► The manuscript reviews the use of switchable probes that can be targeted to specific structures in cells.
► Use of photoswitchable fluorophores for super-resolution microscopy is described.
► Photoactivatable fluorophores and fluorogenic substrates are discussed.
► Localizable indicators based on switchable fluorophores are reviewed.