Nuclear pore targeting of the yeast Pom33 nucleoporin depends on karyopherin and lipid binding.
J Cell Sci
; 128(2): 305-16, 2015 Jan 15.
Article
em En
| MEDLINE
| ID: mdl-25413348
ABSTRACT
Pom33 is an integral membrane protein of the yeast nuclear pore complex (NPC), and it is required for proper NPC distribution and assembly. To characterize the Pom33 NPC-targeting determinants, we performed immunoprecipitation experiments followed by mass spectrometry analyses. This identified a new Pom33 partner, the nuclear import factor Kap123. In vitro experiments revealed a direct interaction between the Pom33 C-terminal domain (CTD) and Kap123. In silico analysis predicted the presence of two amphipathic α-helices within Pom33-CTD. Circular dichroism and liposome co-flotation assays showed that this domain is able to fold into α-helices in the presence of liposomes and preferentially binds to highly curved lipid membranes. When expressed in yeast, under conditions abolishing Pom33-CTD membrane association, this domain behaves as a Kap123-dependent nuclear localization signal (NLS). Although deletion of Pom33 C-terminal domain (Pom33(ΔCTD)-GFP) impaired Pom33 stability and NPC targeting, mutants affecting either Kap123 binding or the amphipathic properties of the α-helices did not display any detectable defect. However, combined impairment of lipid and Kap123 binding affects targeting of Pom33 to NPCs. These data highlight the requirement of multiple determinants and mechanisms for proper NPC localization of Pom33.
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Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Poro Nuclear
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Beta Carioferinas
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Complexo de Proteínas Formadoras de Poros Nucleares
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Proteínas de Saccharomyces cerevisiae
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
J Cell Sci
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
França