Figure 4.

Secreted PTEN-L mediates type I IFN responses and antiviral immunity. (a) Pten^−/− MEFs were treated with the supernatants of HEK293T cell cultures transfected with the following PTEN variants: PTEN-L^atg/ata (ATG/ATA), C297S-L, PTEN and PTEN-L^ΔN21&R6 (ΔN21&R6) or empty vector (EV). Then, cells were infected with VSV-GFP. VSV-GFP replication was observed by microscopy. (b) HEK293T supernatants were collected. Cells were lysed and then subjected to SDS–PAGE. Collected supernatants were incubated with Ni-NTA magnetic agarose beads to pull down His-tagged protein. Treated MEFs were lysed and subjected to SDS–PAGE analysis of secreting and cell-penetrating of PTEN-L. (c) Pten^−/− MEF supernatants were subjected to VSV plaque assays. (d) Pten^−/− MEF cells were lysed in TRIzol to isolate RNA, which was reverse transcribed to cDNA. Quantitative RT-PCR was conducted to measure the relative expression levels of IFN-B1 and CXCL1. The data represent the average of three independent experiments and were analyzed by two-tailed unpaired t test. Graphs show the mean±s.d. (n=3) derived from three independent experiments. *P<0.05, ***P<0.001, ****P<0.0001.