Article (Scientific journals)
Effects of calmodulin on aromatase activity in the preoptic area.
Balthazart, Jacques; Baillien, M.; Charlier, Thierry et al.
2005In Journal of Neuroendocrinology, 17 (10), p. 664-71
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Keywords :
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
Abstract :
[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.
Disciplines :
Endocrinology, metabolism & nutrition
Neurosciences & behavior
Biochemistry, biophysics & molecular biology
Author, co-author :
Balthazart, Jacques  ;  Université de Liège - ULiège > Département des sciences biomédicales et précliniques > Biologie de la différenciation sexuelle du cerveau
Baillien, M.
Charlier, Thierry ;  Université de Liège - ULiège > Département des sciences biomédicales et précliniques > Biologie de la différenciation sexuelle du cerveau
Ball, G. F.
Language :
English
Title :
Effects of calmodulin on aromatase activity in the preoptic area.
Publication date :
2005
Journal title :
Journal of Neuroendocrinology
ISSN :
0953-8194
eISSN :
1365-2826
Publisher :
Blackwell Publishing, Oxford, United Kingdom
Volume :
17
Issue :
10
Pages :
664-71
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 20 April 2009

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