Overexpression of protein kinase B/AKT induces phosphorylation of p70S6K and 4E-BP1 in goat fetal fibroblasts.

Abstract

Protein kinases regulate many processes, including cell growth, metabolism, molecular interactions, and cell proliferation. Protein kinase B (PKB)/AKT (v-AKT mouse thymoma viral oncogene homolog) is an upstream component of mammalian target of rapamycin (mTOR) signaling and mediates pathophysiological processes in several signaling pathways. This study aimed to construct and overexpress a eukaryotic goat AKT expression vector in goat fetal fibroblasts and examine the effects of AKT on the phosphorylation of p70S6K and 4E-BP1. AKT was subcloned into the expression vector pIRES2-DsRed2 to generate pIRES2-DsRed2-AKT, which was transfected into goat fetal fibroblasts with LipofectamineTM 2000. AKT was measured by reverse transcription-polymerase chain reaction in the transgenic cells, and the expression of AKT and phosphorylation of p70S6K (Thr389) and 4E-BP1 (Thr37/46) were analyzed by Western blot. Cell clones that stably emitted red fluorescence were obtained after transfection for 48 h, and the exogenous gene was verified. Exogenous AKT was transcribed, and AKT was overexpressed, inducing the phosphorylation of p70S6K (Thr389) and 4E-BP1 (Thr37/46) in goat fetal fibroblasts. Thus, the overexpression of AKT activates mTOR signaling in goat cells.