NCBI Summary:
The protein encoded by this gene is a serine/threonine kinase and is part of some signal transduction cascades, including the ERK and JNK kinase pathways as well as the NF-kappa-B pathway. The encoded protein is activated by autophosphorylation and requires magnesium as a cofactor in phosphorylating other proteins. This protein has E3 ligase activity conferred by a plant homeodomain (PHD) in its N-terminus and phospho-kinase activity conferred by a kinase domain in its C-terminus. [provided by RefSeq, Mar 2012]
General function
Enzyme
Comment
Cellular localization
Cytoplasmic
Comment
Ovarian function
Follicle atresia
Comment
Let-7g Induces Granulosa Cell Apoptosis by Targeting MAP3K1 in the Porcine Ovary. Rui C et al. (2015) Follicular atresia mainly results from apoptosis of granulosa cells (GCs). Our previous microRNA array data indicated that the miRNA let-7g level increases significantly during porcine ovary follicular atresia. It is uncertain if GCs apoptosis is mediated by microRNA let-7g. In this study, the expression levels of the apoptosis-associated genes CASP3, BAX and BIM were significantly upregulated when let-7g mimic was transfected into porcine GCs, and the anti-apoptotic genes BCL-2 and MCL-1 were significantly downregulated. The apoptosis rate was measured by flow cytometry, and our results indicated that let-7g significantly enhanced GCs apoptosis. In further studies, we found that overexpression of let-7g induced the expression of FoxO1 in GCs and led to nuclear accumulation of dephosphorylated FoxO1. In addition, the effect of let-7g on FoxO1 expression and dephosphorylation resulted from repression of the expression of the MAP3K1 gene in porcine GCs. The site on MAP3K1 mRNA targeted by let-7g was confirmed by luciferase reporter assay. The anti-apoptotic effect of MAP3K1 was validated by silencing MAP3K1 using small interfering RNA technology. In conclusion, our data indicate that let-7g induces porcine GCs apoptosis by inhibiting the MAP3K1 gene, which promotes FoxO1 expression and dephosphorylation with nuclear accumulation.//////////////////