Reference : Effects of calmodulin on aromatase activity in the preoptic area.
Scientific journals : Article
Social & behavioral sciences, psychology : Neurosciences & behavior
Human health sciences : Endocrinology, metabolism & nutrition
Life sciences : Biochemistry, biophysics & molecular biology
http://hdl.handle.net/2268/11610
Effects of calmodulin on aromatase activity in the preoptic area.
English
Balthazart, Jacques mailto [Université de Liège - ULg > Département des sciences biomédicales et précliniques > Biologie de la différenciation sexuelle du cerveau >]
Baillien, M. [> > > >]
Charlier, Thierry mailto [Université de Liège - ULg > Département des sciences biomédicales et précliniques > Biologie de la différenciation sexuelle du cerveau >]
Ball, G. F. [> > > >]
2005
Journal of Neuroendocrinology
Blackwell Publishing
17
10
664-71
Yes
International
0953-8194
1365-2826
Oxford
United Kingdom
[en] aromatisation ; Amino Acid Sequence ; calcium ; Animals ; Aromatase/genetics/metabolism ; Calcium/metabolism ; Calmodulin/physiology ; Coturnix ; Down-Regulation ; Male ; Molecular Sequence Data ; Phosphorylation ; Preoptic Area/enzymology ; Protein Kinases/metabolism ; Sequence Homology, Amino Acid ; Testosterone/metabolism
[en] Oestrogens derived from the neural aromatisation of testosterone play a key role in the activation of male sexual behaviour in many vertebrates. Besides their slow action on gene transcription mediated by the binding to nuclear receptors, oestrogens have now been recognised to have more rapid membrane-based effects on brain function. Rapid changes in aromatase activity, and hence in local oestrogen concentrations, could thus rapidly modulate behavioural responses. We previously demonstrated that calcium-dependent kinases are able to down-regulate aromatase activity after incubations of 10-15 min in phosphorylating conditions. In the present study, in quail hypothalamic homogenates, we show that Ca2+ or calmodulin alone can very rapidly change aromatase activity. Preincubation with 1 mM EGTA or with a monoclonal antibody raised against calmodulin immediately increased aromatase activity. The presence of calmodulin on aromatase purified by immunoprecipitation and electrophoresis was previously identified by western blot and two consensus binding sites for Ca2+-calmodulin are identified here on the deduced amino acid sequence of the quail brain aromatase. The rapid control of brain aromatase activity thus appears to include two mechanisms: (i) an immediate regulatory process that involves the Ca2+-calmodulin binding site and (ii) a somewhat slower phosphorylation by several protein kinases (PKC, PKA but also possibly Ca2+-calmodulin kinases) of the aromatase molecule.
http://hdl.handle.net/2268/11610
also: http://hdl.handle.net/2268/13899
10.1111/j.1365-2826.2005.01355.x

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