Regulation of the TRP Ca2+ channel by INAD in Drosophila photoreceptors.
Drosophila vision involves a G protein-coupled phospholipase C-mediated signaling pathway that leads to membrane depolarization through activation of Na+ and Ca2+ channels. InaD mutant flies have a M442K point mutation and display a slow recovery of the Ca2+ dependent current. We report that anti-INAD antibodies coimmunoprecipitate TRP, identified by its electrophoretic mobility, cross reactivity with anti-TRP antibody, and absence in a null allele trp mutant. This interaction is abolished by the InaD point mutation in vitro and in vivo. Interaction was localized to the 19 amino acid C-terminus of TRP by overlay assays, and to the PDZ domain of INAD, encompassing the point mutation. Given the impaired electrophysiology of the InaD mutant, this novel interaction suggests that INAD functions as a regulatory subunit of the TRP Ca2+ channel.
Shieh
B H
BH
Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-6600, USA.
Zhu
M Y
MY
D000595:Amino Acid Sequence; D000818:Animals; D015220:Calcium Channels / Q000502:physiology*; D017931:DNA Primers / Q000737:chemistry; D029721:Drosophila Proteins; D004331:Drosophila melanogaster; D005136:Eye Proteins / Q000502:physiology*; D007301:Insect Hormones / Q000502:physiology*; D019476:Insect Proteins; D008969:Molecular Sequence Data; D017956:Photoreceptor Cells, Invertebrate / Q000502:physiology*; D017354:Point Mutation; D011485:Protein Binding; D012160:Retina / Q000502:physiology; D015398:Signal Transduction; D013329:Structure-Activity Relationship; D050051:Transient Receptor Potential Channels
D015220:Calcium Channels; D017931:DNA Primers; D029721:Drosophila Proteins; D005136:Eye Proteins; D007301:Insect Hormones; D019476:Insect Proteins; D050051:Transient Receptor Potential Channels; C091568:inaD protein, Drosophila; C063169:trp protein, Drosophila