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Protein kinase B/Akt may regulate G2/M transition in the fertilized mouse egg by changing the localization of p21 Cip1/WAF1
Author(s) -
Wu DiDi,
Feng Chen,
Xu XiaoYan,
Xiao JianYing,
Liu Chao,
Meng Jun,
Wang EnHua,
Yu BingZhi
Publication year - 2011
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.1743
Subject(s) - protein kinase b , microbiology and biotechnology , human fertilization , protein kinase a , kinase , chemistry , biology , phosphorylation , biochemistry , genetics
Abstract Protein kinase B (PKB, also called Akt) is known as a serine/threonine protein kinase. Some studies indicate that the Akt signalling pathway strongly promotes G2/M transition in mammalian cell cycle progression, but the mechanism remains to be clarified, especially in the fertilized mouse egg. Here, we report that the expression of Akt at both the protein and mRNA level was highest in G2 phase, accompanied by a peak of Akt activity. In addition, the subcellular localization of p21 Cip1/WAF1 has been proposed to be critical in the cell cycle. Hence, we detected the expression and localization of p21 Cip1/WAF1 after injecting fertilized mouse eggs with Akt mRNA. In one‐cell stage fertilized embryos microinjected with mRNA coding for a constitutively active myristoylated Akt (myr‐Akt), p21 Cip1/WAF1 was retained in the cytoplasm. Microinjection of mRNA of kinase‐deficient Akt(Akt‐KD) resulted in nuclear localization of p21 Cip1/WAF1 . Meanwhile, microinjection of different types of Akt mRNA affected the phosphorylation status of p21 Cip1/WAF1 . However, there was no obvious difference in the protein expression of p21 Cip1/WAF1 . Therefore, Akt controls the cell cycle by changing the subcellular localization of p21 Cip1/WAF1 , most likely by affecting the phosphorylation status of p21 Cip1/WAF1 . Copyright © 2011 John Wiley & Sons, Ltd.