IFITM3 is interferon-induced transmembrane 3, which plays an extremely key role in anti-proliferation, anti-virus and anti-tumor diseases. To expand our understanding of the role of IFITM3 in yak, this experiment studied its function.
Firstly, the yak ( Bos grunniens ) IFITM3 ( BgIFITM3 ) gene contained a 5’-untranslated region (UTR) (25 bp), a coding region (441 bp), and a 3’-UTR (115 bp). The expression of BgIFITM3 gene in liver was significantly higher than that in heart, spleen, lung and kidney ( P <0.01). BgIFITM3 protein was localized on the yak hepatocyte membrane, and its expression level was increased first and then stabilized from 1 day to 5 years of age. Moreover, the prokaryotic expression vector of BgIFITM3 protein was constructed and expressed successfully, with a molecular weight of 19.5 kDa. Besides, the activity of yak hepatocyte was significantly inhibited after treating with BgIFITM3 protein (10 and 20 μg/mL) ( P <0.01). The expression levels of ERBB-2, IRS-1, PI3KR-1, AKT-1 and MAPK-3 were significantly lower after treating with 20 μg/mL BgIFITM3 protein ( P <0.05). Finally, the activity of HepG2 cells was significantly inhibited after treating with BgIFITM3 protein (1, 10 and 20 μg/mL) ( P <0.05). While the cloning ability and migration ability of HepG2 cells were significantly inhibited after treating with 10 μg/mL BgIFITM3 protein ( P <0.05). The mitochondria of HepG2 cells were concentrated, cristae widened, and the double film density of mitochondria was increased after treating with 10 μg/mL BgIFITM3 protein. After 10 μg/mL BgIFITM3 protein treating, the expression levels of VDAC-2, VDAC-3 , p53 genes were significantly increased, but the expression level of GPX-4 gene was significantly decreased ( P <0.01).
Taken together, the BgIFITM3 protein could inhibit the proliferations of yak hepatocyte and HepG2 cells by regulating the PI3K/Akt pathway or ferroptosis-related genes, respectively. These results benefit for further study of the function of BgIFITM3 protein.