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ZFIN ID: ZDB-PUB-130604-3
Participation of PI3-kinase/Akt signalling in insulin stimulation of p34cdc2 activation in zebrafish oocyte: Phosphodiesterase 3 as a potential downstream target
Das, D., Khan, P.P., and Maitra, S.
Date: 2013
Source: Molecular and Cellular Endocrinology   374(1-2): 46-55 (Journal)
Registered Authors:
Keywords: insulin signalling, PI3K, Akt, phosphodiesterase, oocyte maturation, zebrafish
MeSH Terms:
  • 1-Methyl-3-isobutylxanthine/pharmacology
  • Androstadienes/pharmacology
  • Animals
  • Chromones/pharmacology
  • Cyclin-Dependent Kinases/genetics*
  • Cyclin-Dependent Kinases/metabolism
  • Female
  • Gene Expression Regulation, Developmental/drug effects
  • Hydroxyprogesterones/pharmacology
  • Insulin/pharmacology*
  • Isoenzymes/genetics
  • Isoenzymes/metabolism
  • Meiosis/drug effects
  • Meiosis/genetics
  • Morpholines/pharmacology
  • Oocytes/cytology
  • Oocytes/drug effects*
  • Oocytes/metabolism
  • Phosphatidylinositol 3-Kinase/genetics*
  • Phosphatidylinositol 3-Kinase/metabolism
  • Phosphodiesterase 3 Inhibitors/pharmacology
  • Phosphoric Diester Hydrolases/genetics*
  • Phosphoric Diester Hydrolases/metabolism
  • Phosphorylation
  • Proto-Oncogene Proteins c-akt/genetics*
  • Proto-Oncogene Proteins c-akt/metabolism
  • Quinolones/pharmacology
  • Recombinant Proteins/pharmacology
  • Signal Transduction/drug effects*
  • Zebrafish/genetics
  • Zebrafish/metabolism*
PubMed: 23623869 Full text @ Mol. Cell. Endocrinol.
FIGURES
ABSTRACT

Exposure of fully grown oocytes to growth factors (insulin/IGFs) initiates various signalling cascades that culminate to final stages of oocyte maturation. Regulation of signalling pathways during growth factor-induced meiosis resumption in fish is not well characterized. Here we studied the participation of PI3K/Akt signalling pathway during recombinant human insulin (rh-insulin)-induced meiotic maturation in zebrafish (Danio rerio) oocytes. Priming of defolliculated oocytes in vitro with rh-insulin promotes germinal vesicle breakdown (GVBD) in a dose- and time-dependent manner, an effect sensitive to translation but not transcription inhibition. More than 80% of the oocytes underwent GVBD due to 0.8 IU/ml rh-insulin within 10 h of incubation and the kinetics of p34cdc2 kinase activation corresponded well with GVBD data. PI3K inhibitors, wortmannin and LY294002 blocked insulin, but not 17α, 20β-DHP-induced GVBD. Immunoblot analyses of oocyte extract revealed that phospho-PI3K (p85α) was up regulated within 30–60 min of insulin stimulation followed by phospho-Akt (Ser473) at 60–120 min. Though PI3K/Akt phosphorylation was largely unaffected, pre-incubation with phosphodiesterase (PDE) inhibitors, IBMX and cilostamide, but not rolipram completely blocked rh-insulin-induced p34cdc2 activation and GVBD. These results suggest that PDE3 may be one potential downstream target to PI3K/Akt signalling necessary for rh-insulin-induced GVBD in zebrafish.

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