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The effects of MEK and PKA inhibition on Spire proteins during oocyte maturation

Filiz Tepekoy1, Gokhan Akkoyunlu2

  • 1Department of Histology and Embryology, Faculty of Medicine, Akdeniz University, 07070, Antalya, Turkey. filiztepekoy@gmail.com.

Cellular and Molecular Biology (Noisy-Le-Grand, France)
|December 30, 2023
PubMed

Insights

MEK and PKA inhibition during oocyte maturation affects Spire protein levels crucial for actin nucleation. Inhibition altered Spire-1 and Spire-2 localization and levels, impacting oocyte development.

Area of Science:

  • Cell Biology
  • Developmental Biology
  • Reproductive Biology

Background:

  • Oocyte maturation involves asymmetric division driven by chromosome migration.
  • Actin filaments are essential for chromosome migration during oocyte maturation.
  • Spire proteins (Spire-1 and Spire-2) are involved in actin nucleation.

Purpose of the Study:

  • To investigate the effects of MEK (Mitogen-activated protein kinase kinase) and PKA (Protein Kinase A) inhibition on Spire-1 and Spire-2 protein levels during mouse oocyte maturation.
  • To determine how these inhibitions impact actin nucleation-related proteins and oocyte development.

Main Methods:

  • Oocytes from PMSG-induced BalbC mice were matured in vitro (IVM) with MEK inhibitor (PD98059) and/or PKA inhibitor (H89).
  • Germinal vesicle breakdown (GVBD) and polar body extrusion (PBE) rates were assessed.
  • Spire-1 and Spire-2 protein levels and localization were analyzed using immunofluorescence and western blot.

Main Results:

  • MEK inhibition reduced PBE rates and decreased cortical Spire-1 and Spire-2 levels in oocytes that underwent PBE.
  • PKA inhibition increased cortical Spire-1 in spindle migration stage oocytes and increased cortical and total Spire-2 in PBE oocytes.
  • Combined MEK and PKA inhibition partially compensated for Spire-1 decrease but not Spire-2 levels.

Conclusions:

  • MEK and PKA signaling pathways play distinct roles in regulating Spire protein levels during oocyte maturation.
  • Inhibition of these pathways significantly alters the dynamics of Spire-1 and Spire-2, potentially affecting cytoskeletal organization and developmental progression.
  • These findings highlight the importance of MEK and PKA in controlling actin nucleation factors for successful oocyte maturation.

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