Human KPNA2 blocking peptide

Proper muscle function is dependent on spatial and temporal control of gene expression in myofibers. Myofibers are multinucleated cells that are formed, repaired and maintained by the process of myogenesis in which progenitor myoblasts proliferate, differentiate and fuse. Gene expression is dependent upon proteins that require facilitated nuclear import, however little is known about the regulation of nucleocytoplasmic transport during the formation of myofibers. We analyzed the role of karyopherin alpha (KPNA), a key classical nuclear import receptor, during myogenesis. We established that five karyopherin alpha paralogs are expressed by primary mouse myoblasts in vitro and that their steady-state levels increase in multinucleated myotubes, suggesting a global increase in demand for classical nuclear import during myogenesis. We used siRNA-mediated knockdown to identify paralog-specific roles for KPNA1 and KPNA2 during myogenesis. KPNA1 knockdown increased myoblast proliferation, whereas KPNA2 knockdown decreased proliferation. In contrast, no proliferation defect was observed with KPNA4 knockdown. Only knockdown of KPNA2 decreased myotube growth. These results identify distinct pathways involved in myoblast proliferation and myotube growth that rely on specific nuclear import receptors suggesting that regulation of classical nuclear import pathways likely plays a critical role in controlling gene expression in skeletal muscle. (C) 2011 Elsevier Inc. All rights reserved.

Background: Increased karyopherin alpha 2 (KPNA2) expression has been demonstrated in epithelial ovarian carcinoma (EOC) tissue. However, its role in the disease is not clear. Here, we investigate the mechanism of involvement of KPNA2 in EOC. Methods: Stable cell lines expressing KPNA2, or KPNA2 shRNAs, were constructed. The effects of KPNA2 overexpression and knockdown on EOC cell migration, invasion, and epithelial-to-mesenchymal transition (EMT) were evaluated using relevant assays and western blot analysis. Key components of the Akt/GSK-3 beta/Snail signaling pathway were detected using western blotting and immunofluorescence. Results: KPNA2 overexpression increased the migration and invasion of EOC cells (EFO-21 and SK-OV3); these cells also exhibited characteristics of EMT. Key proteins in the Akt/GSK-3 beta/Snail signaling pathway were also upregulated in cells overexpressing KPNA2. In contrast, knockdown of KPNA2 effectively suppressed migration and invasion of these EOC cells. Conclusions: KPNA2 may reduce the migration and invasion of EOC by inhibiting the Akt/GSK-3 beta/Snail signaling pathway and suppressing EMT.