The light-sensitive dimerizer zapalog reveals distinct modes of immobilization for axonal mitochondria

• Published in: Nature cell biology Vol. 21; no. 6; pp. 768 - 777
• Main Authors: Gutnick, Amos, Banghart, Matthew R., West, Emma R., Schwarz, Thomas L.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.06.2019; Nature Publishing Group
• Subjects: 13; 13/106; 14; 14/19; 14/35; 38; 38/1; 631/57/343/2281; 631/80/128/2343; 631/80/642/333; Actin; Actins - antagonists & inhibitors; Analysis; Animals; Axons - chemistry; Axons - metabolism; Axons - radiation effects; Biomedical and Life Sciences; Bridged Bicyclo Compounds, Heterocyclic - pharmacology; Cancer Research; Cell Biology; Cells; Chlorocebus aethiops; COS Cells; Developmental Biology; Dihydrofolate reductase; Dimerization; Domains; Immobilization; Kinesin; Kinesin - chemistry; Life Sciences; Light; Microtubules - genetics; Microtubules - radiation effects; Mitochondria; Mitochondria - chemistry; Mitochondria - genetics; Mitochondria - radiation effects; Motility; Motors; Neurons - chemistry; Neurons - radiation effects; Photolysis; Polymerization; Polymerization - drug effects; Protein Domains - genetics; Protein Domains - radiation effects; Protein Multimerization - genetics; Protein Multimerization - radiation effects; Protein-protein interactions; Restoration; Stem Cells; Synapses - chemistry; Synapses - genetics; Synapses - radiation effects; Tacrolimus Binding Proteins - chemistry; Tacrolimus Binding Proteins - genetics; Tacrolimus-binding protein; technical-report; Thiazolidines - pharmacology; Vesicular Glutamate Transport Protein 1 - genetics
• DOI: 10.1038/s41556-019-0317-2
• ISSN: 1465-7392

Controlling cellular processes with light can help elucidate their underlying mechanisms. Here we present zapalog, a small-molecule dimerizer that undergoes photolysis when exposed to blue light. Zapalog dimerizes any two proteins tagged with the FKBP and DHFR domains until exposure to light causes its photolysis. Dimerization can be repeatedly restored with uncleaved zapalog. We implement this method to investigate mitochondrial motility and positioning in cultured neurons. Using zapalog, we tether mitochondria to constitutively active kinesin motors, forcing them down the axon towards microtubule (+) ends until their instantaneous release via blue light, which results in full restoration of their endogenous motility. We find that one-third of stationary mitochondria cannot be pulled away from their position and that these firmly anchored mitochondria preferentially localize to VGLUT1-positive presynapses. Furthermore, inhibition of actin polymerization with latrunculin A reduces this firmly anchored pool. On release from exogenous motors, mitochondria are preferentially recaptured at presynapses. Gutnick et al. design a light-sensitive small molecule, zapalog, which reversibly dimerizes any two proteins. Tethering mitochondria to active kinesin motors uncovers distinct modes of mitochondrial motility in axons.