Ca2+-Activated, Fatty Acid-Dependent Guanylate Cyclase in Synaptic Plasma Membranes and Its Requirement for Ca2+ and Mg-GTP in the Activation

Asakawa, Takeo; Takano, Masako; Enomoto, Keiichi; Hayama, Kazuko

doi:10.1007/978-1-4684-4805-4_14

Cited by 2 publications

References 19 publications

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Calmodulin selectively modulates the guanylate cyclase activity by repressing the lipid phase separation temperature in the inner half of the bilayer of rat brain synaptosomal plasma membranes

Kopeikina-Tsiboukidou

Deliconstantinos

1989

Neurochem Res

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The association of [125I-]calmodulin with rat brain synaptosomal plasma membranes, when incubated for 1 h at 25 degrees in the presence or in absence of 20 microM Ca2+, follows a sigmoid path with a Hill coefficient h = 1.79 +/- 0.12 and h = 1.72 +/- 0.11, respectively. The total association of calmodulin with the membrane increased approx. 60%-80% at all the range of calmodulin concentrations used in the presence of 20 microM Ca2+. A three fold increase of guanylate cyclase activity was shown in the presence of low concentrations of calmodulin (up to 10 nM); higher concentrations (up to 40 nM) however, led to a progressive inhibition of the enzyme activity with respect to maximal stimulation. Calmodulin increased the lipid fluidity of synaptosomal plasma membranes labeled with 1,6-diphenyl-1,3,5-hexatriene (DPH), as indicated by the steady-state fluorescence anisotropy [(ro/r)-1]-1. Arrhenius-type plots of [(ro/r)-1]-1 indicated that the lipid separation of the membrane at 22.7 +/- 1.2 degrees was perturbed by calmodulin such that the temperature was reduced to 16.3 +/- 0.9 degrees and 15.5 +/- 0.8 degrees in the absence or in the presence of 20 microM Ca2+. Arrhenius plots of guanylate cyclase and acetylcholinesterase activities exhibited break points at 26.7 +/- 1.4 degrees and 22.3 +/- 1.0 degrees in control synaptosomal plasma membranes, respectively. The break point for the guanylate cyclase was reduced to 16.3 +/- 0.9 degrees in calmodulin treated synaptosomal plasma membranes whereas that of acetylcholinesterase remained unaffected (21.1 +/- 0.9 degrees).(ABSTRACT TRUNCATED AT 250 WORDS)

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Calmodulin selectively modulates the guanylate cyclase activity by repressing the lipid phase separation temperature in the inner half of the bilayer of rat brain synaptosomal plasma membranes

Kopeikina-Tsiboukidou

Deliconstantinos

1989

Neurochem Res

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Coordinate Interactions of Cyclic Nucleotide and Phospholipid Metabolizing Pathways in Calcium-Dependent Cellular Processes

Laychock

1989

Current Topics in Cellular Regulation

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Ca2+-Activated, Fatty Acid-Dependent Guanylate Cyclase in Synaptic Plasma Membranes and Its Requirement for Ca2+ and Mg-GTP in the Activation

Cited by 2 publications

References 19 publications

Calmodulin selectively modulates the guanylate cyclase activity by repressing the lipid phase separation temperature in the inner half of the bilayer of rat brain synaptosomal plasma membranes

Calmodulin selectively modulates the guanylate cyclase activity by repressing the lipid phase separation temperature in the inner half of the bilayer of rat brain synaptosomal plasma membranes

Coordinate Interactions of Cyclic Nucleotide and Phospholipid Metabolizing Pathways in Calcium-Dependent Cellular Processes

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