Abstract
Nup145p is an essential yeast nucleoporin involved in nuclear export of polyadenylated RNAs. We demonstrate here that Nup145p is cleaved in vivo to yield two functionally distinct domains: a carboxy-terminal domain (C-Nup145p) which is located at the nuclear pore complex (NPC) and assembles into the Nup84p complex, and a GLFG-containing amino-terminal domain (N-Nup145p) which is not part of this complex. Whereas the essential C-Nup145p accomplishes the functions required for efficient mRNA export and normal NPC distribution, N-Nup145p, which is homologous to the GLFG-containing nucleoporins Nup100p and Nup116p, is not necessary for cell growth. However, the N-Nup145p becomes essential in a nup188 mutant background. Strikingly, generation of a free N-domain is a prerequisite for complementation of this peculiar synthetic lethal mutant. These data suggest that N- and C-domains of Nup145p perform independent functions, and that the in vivo cleavage observed is of functional importance.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Biological Transport / physiology
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Blotting, Western
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Electrophoresis, Polyacrylamide Gel
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Fungal Proteins / analysis
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Fungal Proteins / chemistry*
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Fungal Proteins / genetics
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Fungal Proteins / metabolism*
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Microscopy, Electron
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Molecular Sequence Data
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Mutagenesis, Site-Directed / genetics
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Nuclear Envelope / chemistry*
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Nuclear Envelope / metabolism
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Nuclear Pore Complex Proteins*
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Nuclear Proteins / metabolism
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Protein Processing, Post-Translational
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RNA, Fungal / metabolism
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RNA, Messenger / metabolism
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RNA-Binding Proteins / analysis
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RNA-Binding Proteins / chemistry*
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RNA-Binding Proteins / genetics
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RNA-Binding Proteins / metabolism*
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / metabolism
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Saccharomyces cerevisiae Proteins*
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Sequence Homology, Amino Acid
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Staphylococcal Protein A / genetics
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Yeasts / genetics
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Yeasts / growth & development
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Yeasts / metabolism
Substances
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Fungal Proteins
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NUP145 protein, S cerevisiae
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NUP84 protein, S cerevisiae
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Nuclear Pore Complex Proteins
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Nuclear Proteins
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RNA, Fungal
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RNA, Messenger
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RNA-Binding Proteins
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Recombinant Fusion Proteins
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Saccharomyces cerevisiae Proteins
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Staphylococcal Protein A