Zhang, H. et al. Nat. Chem. Biol. https://doi.org/10.1038/nchembio.2456 (2017).

Optogenetic tools for controlling protein dimerization have become invaluable for probing cellular activities and pathways. Zhang et al. introduce two variants of the previously developed dimerizer NTH that offer improved features, such as increased light sensitivity and reversibility. NTH and its derivatives, CTH and TNH, are composed of three modules: Escherichia coli dihydrofolate reductase (eDHFR), a photocaged form of the eDHFR ligand trimethoprim fused to the Halo ligand, and the Halo-tag protein. In the presence of light, the ligand is uncaged, and this brings the eDHFR and the Halo-tag protein (and any proteins to which they are fused) together. The authors showcase the improved dimerizers by using them to study kinetochore function, showing that the molecular motor CENP-E is involved in directional chromosome transport and maintenance of metaphase alignment.