High impact information on Rya-r44F

• Treatment with the drug ryanodine, a highly specific modulator of ryanodine receptor channel activity, also inhibited muscle function, and, at high levels, completely blocked hypodermal muscle contraction [1].
• Drosophila homologs of two mammalian intracellular Ca(2+)-release channels: identification and expression patterns of the inositol 1,4,5-triphosphate and the ryanodine receptor genes [2].
• These results suggest that PKD2 cooperates with the ryanodine receptor to promote optimal muscle contractility through intracellular Ca(2+) homeostasis [3].
• Consistent with this, Pkd2 interacted strongly with a ryanodine receptor mutation, causing a synergistic reduction of larval body wall contraction rate that is normally regulated through Ca(2+) oscillation during excitation-contraction coupling in the skeletal muscle [3].
• Ryanodine receptor was expressed mainly in the digestive tract and parts of the nervous system [4].

Biological context of Rya-r44F

• Genetic interaction studies suggest that failed regulation of the muscle calcium release channel, the ryanodine receptor, is the major defect underlying the Cam7 phenotype [5].
• The nucleotide sequence of a 25.7 kilobase Drosophila melanogaster genomic DNA segment containing a gene for a ryanodine receptor/calcium release channel homologue has been determined [6].
• These results suggest that RyR is involved with Ca(2+) regulation in the nonreceptive cell area of both fly and honeybee photoreceptors, but that it may contribute to Ca(2+) regulation close to the phototransduction compartment only in the latter cell [7].

Anatomical context of Rya-r44F

• In both Calliphora and Drosophila photoreceptors, the anti-RyR antibody provides punctate labeling throughout the cell body [7].
• By confocal immunofluorescence microscopy on honeybee eyes, RyR is detected within the photoreceptors and shows a nonhomogeneous distribution over the endoplasmic reticulum (ER) [7].
• The submicrovillar ER cisternae associated with the base of the microvilli, however, are only lightly labeled for RyR [7].
• These phenomena have been documented in Paramecium, in Drosophila, in vertebrate photoreceptors and olfactory receptors, as well as in ryanodine receptor Ca(2+)-release channels [8].
• Double labeling studies have demonstrated further that RyR is localized at distinct ER elements close to the light-sensitive microvilli and juxtaposed to adherens junctions [7].

Associations of Rya-r44F with chemical compounds

• In both honeybee and fly eyes, the antibody identifies a single protein that comigrates with muscle RyR on sodium dodecylsulfate (SDS) polyacrylamide gels demonstrating that RyR is present in this tissue [7].
• Transcripts encoding two calcium-release channels, the ryanodine receptor and the inositol trisphosphate receptor, are detectable in the tubule by reverse transcription-polymerase chain reaction [9].
• An abnormal ketamine response in mutants defective in the ryanodine receptor gene ryr-1 (unc-68) of Caenorhabditis elegans [10].
• This novel insecticide mode of action seems to be restricted to specific RyR subtypes because the phthalic acid diamides reported here had almost no effect on mammalian type 1 ryanodine receptors [11].
• Because the effect can be reproduced using a calcium ionophore (ionomycin treatment) as well as blocked by the inhibition of the muscle ryanodine receptor (tetracaine treatment), the involvement of calcium in this process seems likely [12].

Other interactions of Rya-r44F

• The predicted functional consequences of these changes are consonant with the in vivo phenotype, and indicate that D-RyR is one, if not the major, target affected by the V91G mutation in CaM [13].

Analytical, diagnostic and therapeutic context of Rya-r44F

• Western blotting and indirect immunofluorescence staining confirm cross-reactivity of the antibody with insect muscle RyR [7].
• When RNAi designed to knock down the ryanodine receptor (RyR) was tested, there was no change in the calcium increase detected in response to CCh, consistent with a failure to detect RyRs in S2-DM1 cells using RT-PCR [14].
• Molecular cloning of cDNA encoding a drosophila ryanodine receptor and functional studies of the carboxyl-terminal calcium release channel [15].

References