A serine/threonine-specific protein kinase B (PKB), also known as Akt, is a key factor in the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway that regulates cell survival, metabolism and proliferation. Akt phosphorylates many downstream specific substrates, which subsequently control the nuclear envelope breakdown (NEBD), centrosome maturation, spindle assembly, chromosome segregation, and cytokinesis. In vertebrates, Akt is also an important player during oogenesis and preimplantation development. In the signaling pathways regulating mRNA translation, Akt is involved in the control of mammalian target of rapamycin complex 1 (mTORC1) and thereby regulates the activity of a translational repressor, the eukaryotic initiation factor 4E (eIF4E) binding protein 1 (4E-BP1). In this review, we summarize the functions of Akt in mitosis, meiosis and early embryonic development. Additionally, the role of Akt in the regulation of mRNA translation is addressed with respect to the significance of this process during early development.

• Klíčová slova
• Akt kinase, early embryo, mRNA translation, mTORC1, meiosis, mitosis, oocyte, spindle,
• MeSH
• 1-fosfatidylinositol-3-kinasa metabolismus   MeSH
• embryonální vývoj MeSH
• fosfatidylinositol-3-kinasy * metabolismus   MeSH
• fosfoproteiny metabolismus   MeSH
• fosforylace genetika   MeSH
• oocyty metabolismus   MeSH
• oogeneze MeSH
• protein-serin-threoninkinasy metabolismus   MeSH
• protoonkogenní proteiny c-akt * metabolismus   MeSH
• savci metabolismus   MeSH
• signální transdukce MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• 1-fosfatidylinositol-3-kinasa MeSH
• fosfatidylinositol-3-kinasy * MeSH
• fosfoproteiny MeSH
• protein-serin-threoninkinasy MeSH
• protoonkogenní proteiny c-akt * MeSH

The extracellular matrix (ECM) is an essential structure with biological activities. It has been shown that the ECM influences gene expression via cytoskeletal components and the gene expression is dependent upon cell interactions with molecules and hormones. The development of ovarian follicles is a hormone dependent process. The surge in the luteinizing hormone triggers ovulatory changes in oocyte microenvironment. In this review, we discuss how proteolytic cleavage affects formation of cumulus ECM following hormonal stimulation; in particular, how the specific proteasome inhibitor MG132 affects gonadotropin-induced cytoskeletal structure, the organization of cumulus ECM, steroidogenesis, and nuclear maturation. We found that after the inhibition of proteolytic cleavage, gonadotropin-stimulated oocyte-cumulus complexes (OCCs) were without any signs of cumulus expansion; they remained compact with preserved cytoskeletal F-actin-rich transzonal projections through the oocyte investments. Concomitantly, a significant decrease was detected in progesterone secretion and in the expression of gonadotropin-stimulated cumulus expansion-related transcripts, such as HAS2 and TNFAIP6. In agreement, the covalent binding between hyaluronan and the heavy chains of serum-derived the inter-alpha-trypsin inhibitor, essential for the organization of cumulus ECM, was missing.

• Klíčová slova
• extracellular matrix, hyaluronan, oocyte–cumulus complex, proteasome,
• MeSH
• buněčné mikroprostředí fyziologie   MeSH
• extracelulární matrix fyziologie   MeSH
• lidé MeSH
• oocyty fyziologie   MeSH
• ovariální folikul fyziologie   MeSH
• proteolýza MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Fertilization of the mammalian oocyte requires interactions between spermatozoa and expanded cumulus extracellular matrix (ECM) that surrounds the oocyte. This review focuses on key molecules that play an important role in the formation of the cumulus ECM, generated by the oocyte-cumulus complex. In particular, the specific inhibitors (AG1478, lapatinib, indomethacin and MG132) and progesterone receptor antagonist (RU486) exerting their effects through the remodeling of the ECM of the cumulus cells surrounding the oocyte have been described. After gonadotropin stimulus, cumulus cells expand and form hyaluronan (HA)-rich cumulus ECM. In pigs, the proper structure of the cumulus ECM depends on the interaction between HA and serum-derived proteins of the inter-alpha-trypsin inhibitor (IαI) protein family. We have demonstrated the synthesis of HA by cumulus cells, and the presence of the IαI, tumor necrosis factor-alpha-induced protein 6 and pentraxin 3 in expanding oocyte-cumulus complexes (OCC). We have evaluated the covalent linkage of heavy chains of IαI proteins to HA, as the principal component of the expanded HA-rich cumulus ECM, in porcine OCC cultured in medium with specific inhibitors: AG1478 and lapatinib (both inhibitors of epidermal growth factor receptor tyrosine kinase activity); MG132 (a specific proteasomal inhibitor), indomethacin (cyclooxygenase inhibitor); and progesterone receptor antagonist (RU486). We have found that both RU486 and indomethacin does not disrupt the formation of the covalent linkage between the heavy chains of IαI to HA in the expanded OCC. In contrast, the inhibitors AG1478 and lapatinib prevent gonadotropin-induced cumulus expansion. Finally, the formation of oocyte-cumulus ECM relying on the covalent transfer of heavy chains of IαI molecules to HA has been inhibited in the presence of MG132.

• Klíčová slova
• extracellular matrix, hyaluronan, inter-alpha-trypsin inhibitor, oocyte-cumulus complexes, pentraxin 3, tumor necrosis factor-alpha-induced protein 6,
• MeSH
• C-reaktivní protein metabolismus   MeSH
• extracelulární matrix účinky léků   metabolismus   MeSH
• kumulární buňky cytologie   účinky léků   metabolismus   MeSH
• kyselina hyaluronová metabolismus   MeSH
• mifepriston farmakologie   MeSH
• molekuly buněčné adheze metabolismus   MeSH
• oocyty cytologie   metabolismus   MeSH
• rozmnožování účinky léků   MeSH
• sérový amyloidový protein metabolismus   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• C-reaktivní protein MeSH
• kyselina hyaluronová MeSH
• mifepriston MeSH
• molekuly buněčné adheze MeSH
• PTX3 protein MeSH Prohlížeč
• sérový amyloidový protein MeSH
• Tnfaip6 protein, mouse MeSH Prohlížeč