Protein phosphatase PP1-NIPP1 activates mesenchymal genes in HeLa cells

The deletion of the protein phosphatase-1 (PP1) regulator known as Nuclear Inhibitor of PP1 (NIPP1) is embryonic lethal during gastrulation, hinting at a key role of PP1-NIPP1 in lineage specification. Consistent with this notion we show here that a mild, stable overexpression of NIPP1 in HeLa cells caused a massive induction of genes of the mesenchymal lineage, in particular smooth/cardiac-muscle and matrix markers. This reprogramming was associated with the formation of actin-based stress fibers and retracting filopodia, and a reduced proliferation potential. The NIPP1-induced mesenchymal transition required functional substrate and PP1-binding domains, suggesting that it involves the selective dephosphorylation of substrates of PP1-NIPP1.publisher: Elsevier articletitle: Protein phosphatase PP1-NIPP1 activates mesenchymal genes in HeLa cells journaltitle: FEBS Letters articlelink: http://dx.doi.org/10.1016/j.febslet.2015.04.017 content_type: article copyright: Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.status: publishe