Identification of a putative nuclear localization signal in the tumor suppressor maspin sheds light on its nuclear import regulation

The tumor suppressor activity of maspin (mammary serine protease inhibitor) has been associated with its nuclear localization. In this study we explore the regulation of maspin nuclear translocation. An in vitro nuclear import assay suggested that maspin can passively enter the nucleus. However, in ...

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Detalles Bibliográficos
Autores: Reina, Jeffrey, Zhou, Lixin, Fontes, Marcos R. M. [UNESP], Panté, Nelly, Cella, Nathalie
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2019
País:Brasil
Institución:Universidade Estadual Paulista (UNESP)
Repositorio:Repositório Institucional da UNESP
Idioma:inglés
OAI Identifier:oai:repositorio.unesp.br:11449/187836
Acceso en línea:http://dx.doi.org/10.1002/2211-5463.12626
http://hdl.handle.net/11449/187836
Access Level:acceso abierto
Palabra clave:import assay
mammary serine protease inhibitor
maspin
nuclear localization signal
nuclear transport
tumor suppressor
Descripción
Sumario:The tumor suppressor activity of maspin (mammary serine protease inhibitor) has been associated with its nuclear localization. In this study we explore the regulation of maspin nuclear translocation. An in vitro nuclear import assay suggested that maspin can passively enter the nucleus. However, in silico analysis identified a putative maspin nuclear localization signal (NLS), which was able to mediate the nuclear translocation of a chimeric protein containing this NLS fused to five green fluorescent protein molecules in tandem (5GFP). Dominant-negative Ran-GTPase mutants RanQ69L or RanT24N suppressed this process. Unexpectedly, the full-length maspin fused to 5GFP failed to enter the nucleus. As maspin's putative NLS is partially hidden in its three-dimensional structure, we suggest that maspin nuclear transport could be conformationally regulated. Our results suggest that maspin nuclear translocation involves both passive and active mechanisms.