A Drosophila mutant defective in extracellular calcium-dependent photoreceptor deactivation and rapid desensitization

Rama Ranganathan, Greg L. Harris, Charles F. Stevens, Charles S. Zuker

Research output: Contribution to journalArticle

158 Scopus citations

Abstract

CALCIUM is involved in the adaptation of vertebrate photoreceptors to light1,2 and may have a similar role in invertebrate phototransduction3,4. But the molecular mechanisms mediating this stimulus-dependent regulation are not well understood in any G protein-coupled transduction system. We have developed a preparation of isolated Drosophila photoreceptors that has allowed us to carry out an electrophysiological characterization of the light-activated response in these sensory neurons using patch-clamp techniques. We report here that extracellular calcium entering through the light-activated conductance is a key regulator of both the activation and deactivation phases of the phototransduction cascade, and that inaC mutant photoreceptors5 are specifically defective in the calcium-dependent deactivation mechanism. These data suggest that the light-dependent calcium influx inactivates this cascade through a biochemical pathway that requires the inaC gene product, and that this mechanism represents a molecular basis for stimulus-dependent regulation of visual transduction in Drosophila photoreceptors.

Original languageEnglish (US)
Pages (from-to)230-232
Number of pages3
JournalNature
Volume354
Issue number6350
DOIs
StatePublished - Jan 1 1991

ASJC Scopus subject areas

  • General

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