Gutnick, A. et al. Nat. Cell Biol. 21, 768–777 (2019).

Chemical inducers of dimerization (CIDs) are useful tools for bringing specifically tagged proteins together or for sequestering such proteins at a particular place in the cell. However, commonly used CIDs such as rapalogs do not afford spatiotemporal control over their action, and they result in irreversible dimerization of target proteins. Gutnick et al. describe zapalog, a light-sensitive dimerizer that undergoes photolysis upon blue light illumination. Zapalog consists of two handles, one for binding to the DHFR domain and one for binding to the FKBP domain. Thus, proteins of interest need to be tagged with these domains. The researchers used their tool to study mitochondrial motility in axons by controlling the interaction between mitochondria and kinesin. They found that one population of mitochondria was stably anchored at presynaptic sites while another pool of mitochondria was motile.