Appearance of a novel Ca2+ influx pathway in Sf9 insect cells following expression of the transient receptor potential-like (trpl) protein of Drosophila

Biochem Biophys Res Commun. 1994 Jun 15;201(2):1050-6. doi: 10.1006/bbrc.1994.1808.


Activation of phospholipase C, elevation of free cytosolic Ca2+ concentration ([Ca2+]i) and stimulation of Ca2+ influx have been implicated in Drosophila phototransduction. Electrophysiological studies suggest that trp and trpl proteins may be important for the light-activated Ca2+ current found in Drosophila photoreceptor cells. Although these proteins exhibit homologies to voltage-gated Ca2+ and Na+ channels, their actual function in insect cells and their relation to proteins involved in mammalian cell Ca2+ signaling remains unknown. In the present study, [Ca2+]i was examined in fura-2-loaded Sf9 insect cells infected with recombinant baculovirus containing cDNA for the trpl protein. Ca2+ influx was examined by use of Ba2+, a Ca2+ surrogate that is not a substrate for Ca(2+)-pumps or carriers and by measurement of whole-cell membrane currents. The results suggest that expression of trpl is associated with appearance of a Ca2+ permeable, non-selective cation channel formed by the trpl protein.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Barium / metabolism
  • Calcium / metabolism*
  • Calmodulin-Binding Proteins / biosynthesis
  • Calmodulin-Binding Proteins / physiology*
  • Carbachol / pharmacology
  • Cell Line
  • Drosophila / metabolism*
  • Drosophila Proteins*
  • Ion Channels / physiology*
  • Kinetics
  • Membrane Potentials
  • Membrane Proteins / biosynthesis
  • Membrane Proteins / physiology*
  • Moths
  • Receptors, Muscarinic / biosynthesis
  • Receptors, Muscarinic / drug effects
  • Receptors, Muscarinic / metabolism
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / drug effects
  • Recombinant Proteins / metabolism
  • Transfection
  • Transient Receptor Potential Channels


  • Calmodulin-Binding Proteins
  • Drosophila Proteins
  • Ion Channels
  • Membrane Proteins
  • Receptors, Muscarinic
  • Recombinant Proteins
  • Transient Receptor Potential Channels
  • trpl protein, Drosophila
  • Barium
  • Carbachol
  • Calcium