Nuclear import of Pin1 is mediated by a novel sequence in the PPIase domain

Pin1 actively regulates diverse biological/pathological processes, but little is known about the regulatory mechanisms of its cellular localization. In this study, we report that the endogenous Pin1 is distributed in both nucleus and cytoplasm. We found that point mutations of several basic amino acids in the PPIase domain of Pin1 significantly compromise its nuclear localization. Such inhibition is independent of Pin1 enzymatic activity, and is mainly due to the defects in the nuclear import. A novel sequence harboring these residues was identified as a putative nuclear localization signal (NLS) of Pin1. Importin α5 of the nuclear import machinery was found to interact with Pin1.Structured summary:MINT-6803320: PIN1 (uniprotkb:Q13255) and importin alpha 5 (uniprotkb:P52294) physically interact (MI:0218) by anti tag coimmunoprecipitation (MI:0007)MINT-6803333: importin alpha 3 (uniprotkb:O00505) and PIN1 (uniprotkb:Q13255) physically interact (MI:0218) by anti tag coimmunoprecipitation (MI:0007)MINT-6803357: PIN1 (uniprotkb:Q13255) physically interacts (MI:0218) with importin alpha 5 (uniprotkb:P52294) by anti bait coimmunoprecipitation (MI:0006)MINT-6803345: St3 (uniprotkb:P40763) and importin alpha 5 (uniprotkb:P52294) physically interact (MI:0218) by anti tag coimmunoprecipitation (MI:0007)