Novel Ca2+ channels underlying transduction in Drosophila photoreceptors: implications for phosphoinositide-mediated Ca2+ mobilization

Trends Neurosci. 1993 Sep;16(9):371-6. doi: 10.1016/0166-2236(93)90095-4.

Abstract

Drosophila photoreceptors are excellent models for studies of the ubiquitous phosphoinositide signalling cascade. Recent studies suggest that light-induced phosphoinositide hydrolysis in Drosophila leads to the activation of two classes of channels. One is selective for Ca2+ and absent in the transient receptor potential mutant trp. The trp gene product, which shows some structural similarity to vertebrate voltage-gated Ca2+ channels, may thus define a novel family of second-messenger-operated Ca2+ channels generally responsible for the widespread but poorly understood phenomenon of phosphoinositide-mediated Ca2+ entry. The other channel is a non-selective cation channel that requires Ca2+ for activation. As well as being a major charge carrier for the light-induced current, Ca2+ influx via the trp-dependent channels appears to be required for refilling Ca2+ stores sensitive to inositol 1,4,5-trisphosphate and for feedback regulation (light adaptation) of the transduction cascade.

Publication types

  • Review

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Calcium Channels / physiology*
  • Drosophila / physiology*
  • Phosphatidylinositols / physiology*
  • Photoreceptor Cells, Invertebrate / physiology*
  • Signal Transduction / physiology*

Substances

  • Calcium Channels
  • Phosphatidylinositols
  • Calcium