Differential effect of PKA on the Ca2+ release kinetics of the type I and III Insp3 receptors

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The effects of protein kinase A (PKA) on the inositol 1,4,5-trisphosphate (InsP(3)) receptor isoforms type I and type III were studied. The effects of PKA on the extent and rate constants for InsP(3)-induced Ca(2+) release (IICR) were different for the two isoforms. The effects of PKA on the type I isoform showed a biphasic relationship dependent upon the concentration of PKA used. At low concentrations of PKA (200U/ml) the extent and rate constants decreased. The type III isoform showed only an increase in the extent of IICR and not in the rate constants. The effects of PKA on the type I InsP(3) receptor using single channel electrophysiological studies were also investigated. The stimulatory effect of PKA is due to an increase in conductance levels and not to a change in the mean open time of the channel.


Original languageEnglish
Pages (from-to)121-126
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number1
Publication statusPublished - 28 Feb 2003


  • protein kinase A, InsP(3) receptors, isoforms, Ca2+ channel, phosphorylation