Karyopherin alpha 1 regulates satellite cell proliferation and survival by modulating nuclear import

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Item Type:	Article
Title:	Karyopherin alpha 1 regulates satellite cell proliferation and survival by modulating nuclear import
Creators Name:	Choo, H.J., Cutler, A., Rother, F., Bader, M. and Pavlath, G.K.
Abstract:	Satellite cells are stem cells with an essential role in skeletal muscle repair. Precise regulation of gene expression is critical for proper satellite cell quiescence, proliferation, differentiation and self-renewal. Nuclear proteins required for gene expression are dependent on the nucleocytoplasmic transport machinery to access to nucleus, however little is known about regulation of nuclear transport in satellite cells. The best characterized nuclear import pathway is classical nuclear import which depends on a classical nuclear localization signal (cNLS) in a cargo protein and the heterodimeric import receptors, karyopherin alpha (KPNA) and beta (KPNB). Multiple KPNA1 paralogs exist and can differ in importing specific cNLS proteins required for cell differentiation and function. We show that transcripts for six Kpna paralogs underwent distinct changes in mouse satellite cells during muscle regeneration accompanied by changes in cNLS proteins in nuclei. Depletion of KPNA1, the most dramatically altered KPNA, caused satellite cells in uninjured muscle to prematurely activate, proliferate and undergo apoptosis leading to satellite cell exhaustion with age. Increased proliferation of satellite cells led to enhanced muscle regeneration at early stages of regeneration. In addition, we observed impaired nuclear localization of two key KPNA1 cargo proteins: p27, a cyclin-dependent kinase inhibitor associated with cell cycle control and lymphoid enhancer factor 1, a critical cotranscription factor for beta-catenin. These results indicate that regulated nuclear import of proteins by KPNA1 is critical for satellite cell proliferation and survival and establish classical nuclear import as a novel regulatory mechanism for controlling satellite cell fate.
Keywords:	Nuclear Import, Importin alpha 5, Satellite Cells, cNLS Proteins, Karyopherin alpha 1, KPNA1, Animals, Mice
Source:	Stem Cells
ISSN:	1066-5099
Publisher:	Wiley-Blackwell
Volume:	34
Number:	11
Page Range:	2784-2797
Date:	November 2016
Additional Information:	Copyright © 2016 AlphaMed Press.
Official Publication:	https://doi.org/10.1002/stem.2467
External Fulltext:	View full text on PubMed Central
PubMed:	View item in PubMed

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