NCBI Summary:
The protein encoded by this gene is a member of the MAP kinase family. MAP kinases act as an integration point for multiple biochemical signals, and are involved in a wide variety of cellular processes such as proliferation, differentiation, transcription regulation and development. This kinase is specifically activated by mitogen-activated protein kinase kinase 5 (MAP2K5/MEK5). It is involved in the downstream signaling processes of various receptor molecules including receptor type kinases, and G protein-coupled receptors. In response to extracelluar signals, this kinase translocates to cell nucleus, where it regulates gene expression by phosphorylating, and activating different transcription factors. Four alternatively spliced transcript variants of this gene encoding two distinct isoforms have been reported. [provided by RefSeq, Jul 2008]
General function
Intracellular signaling cascade
Comment
Cellular localization
Cytoplasmic
Comment
Ovarian function
Early embryo development
Comment
Expression regulated by
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Ovarian localization
Oocyte
Comment
Phosphorylated ERK5/BMK1 transiently accumulates within division spindles in mouse oocytes and preimplantation embryos. Maciejewska Z et al. MAP kinases of the ERK family play important roles in oocyte maturation, fertilization, and early embryo development. The role of the signaling pathway involving ERK5 MAP kinase during meiotic and mitotic M-phase of the cell cycle is not well known. Here, we studied the localization of the phosphorylated, and thus potentially activated, form of ERK5 in mouse maturing oocytes and mitotically dividing early embryos. We show that phosphorylation/dephosphorylation, i.e. likely activation/inactivation of ERK5, correlates with M-phase progression. Phosphorylated form of ERK5 accumulates in division spindle of both meiotic and mitotic cells, and precisely co-localizes with spindle microtubules at metaphase. This localization changes drastically in the anaphase, when phospho-ERK5 completely disappears from microtubules and transits to the cytoplasmic granular, vesicle-like structures. In telophase oocytes it becomes incorporated into the midbody. Dynamic changes in the localization of phospho-ERK5 suggests that it may play an important role both in meiotic and mitotic division. (Folia Histochemica et Cytobiologica 2011, Vol. 49, No. 3, 528-534).