Antiapoptotic Activity of PAI-2 is Affected by Its Cellular Localization

Purpose: To study the effect of cellular location of PAI-2 on its antiapoptotic activity. Methods: The cDNA of PAI-2-NLS mutant, 3′-terminus of which a nuclear localization sequence was inserted downstream, was cloned in-frame into eukaryotic expression vector, pEGFPC3, producing pEGFPC3-PAI2-NLS. After transfected into HeLa cells, different distributions of PAI-2 and PAI2-NLS mutant in HeLa cells were observed through fluorescence microscopy, and MTT assay was used to analyze the antiapoptotic activity of this PAI-2 mutant. Results: Due to the nuclear localization sequence, almost all PAI-2 mutants entered nuclei, while wide type PAI-2 distributed evenly in the cytoplasm and nucleus. The results of MTT assay indicated that if PAI-2 was located in the nuclei, it would lose its antiapoptotic activity against TNF-α. Conclusions: All the results demonstrate that antiapoptotic activity of PAI-2 is affected by its cellular localization. In addition, the treatment of TNF-α would not affect the distribution of PAI-2 in HeLa cells.