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

Nat Cell Biol. 2019 Jun;21(6):768-777. doi: 10.1038/s41556-019-0317-2. Epub 2019 May 6.

Abstract

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / antagonists & inhibitors
  • Animals
  • Axons / chemistry
  • Axons / metabolism*
  • Axons / radiation effects
  • Bridged Bicyclo Compounds, Heterocyclic / pharmacology
  • COS Cells
  • Chlorocebus aethiops
  • Kinesin / chemistry
  • Light
  • Microtubules / genetics
  • Microtubules / radiation effects
  • Mitochondria / chemistry
  • Mitochondria / genetics*
  • Mitochondria / radiation effects
  • Neurons / chemistry
  • Neurons / radiation effects
  • Photolysis*
  • Polymerization / drug effects
  • Protein Domains / genetics
  • Protein Domains / radiation effects
  • Protein Multimerization / genetics
  • Protein Multimerization / radiation effects*
  • Synapses / chemistry
  • Synapses / genetics
  • Synapses / radiation effects
  • Tacrolimus Binding Proteins / chemistry
  • Tacrolimus Binding Proteins / genetics
  • Thiazolidines / pharmacology
  • Vesicular Glutamate Transport Protein 1 / genetics

Substances

  • Actins
  • Bridged Bicyclo Compounds, Heterocyclic
  • Thiazolidines
  • Vesicular Glutamate Transport Protein 1
  • Kinesin
  • Tacrolimus Binding Proteins
  • latrunculin A