Arrestin translocation is stoichiometric to rhodopsin isomerization and accelerated by phototransduction in Drosophila photoreceptors

Neuron. 2010 Sep 23;67(6):997-1008. doi: 10.1016/j.neuron.2010.08.024.


Upon illumination, visual arrestin translocates from photoreceptor cell bodies to rhodopsin and membrane-rich photosensory compartments, vertebrate outer segments or invertebrate rhabdomeres, where it quenches activated rhodopsin. Both the mechanism and function of arrestin translocation are unresolved and controversial. In dark-adapted photoreceptors of the fruitfly Drosophila, confocal immunocytochemistry shows arrestin (Arr2) associated with distributed photoreceptor endomembranes. Immunocytochemistry and live imaging of GFP-tagged Arr2 demonstrate rapid reversible translocation to stimulated rhabdomeres in stoichiometric proportion to rhodopsin photoisomerization. Translocation is very rapid in normal photoreceptors (time constant <10 s) and can also be resolved in the time course of electroretinogram recordings. Genetic elimination of key phototransduction proteins, including phospholipase C (PLC), Gq, and the light-sensitive Ca2+-permeable TRP channels, slows translocation by 10- to 100-fold. Our results indicate that Arr2 translocation in Drosophila photoreceptors is driven by diffusion, but profoundly accelerated by phototransduction and Ca2+ influx.

Publication types

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

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Arrestins / genetics
  • Arrestins / metabolism*
  • Calcium / metabolism
  • Dark Adaptation / genetics
  • Drosophila
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Electroretinography / methods
  • Endocytosis / physiology
  • Gene Expression Regulation / radiation effects
  • Green Fluorescent Proteins / genetics
  • Isomerism
  • Light
  • Light Signal Transduction / genetics
  • Light Signal Transduction / physiology*
  • Mutation / genetics
  • Phospholipase C beta / genetics
  • Photoreceptor Cells, Invertebrate / physiology*
  • Protein Transport / physiology
  • Rhodopsin / metabolism*
  • Spectrum Analysis
  • Time Factors
  • Transient Receptor Potential Channels / genetics


  • Arr2 protein, Drosophila
  • Arrestins
  • Drosophila Proteins
  • Transient Receptor Potential Channels
  • Green Fluorescent Proteins
  • metarhodopsins
  • Rhodopsin
  • NorpA protein, Drosophila
  • Phospholipase C beta
  • Calcium