A visual screen of a GFP-fusion library identifies a new type of nuclear envelope membrane protein.
The nuclear envelope (NE) is a distinct subdomain of the ER, but few membrane components have been described that are specific to it. We performed a visual screen in tissue culture cells to identify proteins targeted to the NE. This approach does not require assumptions about the nature of the association with the NE or the physical separation of NE and ER. We confirmed that screening a library of fusions to the green fluorescent protein can be used to identify proteins targeted to various subcompartments of mammalian cells, including the NE. With this approach, we identified a new NE membrane protein, named nurim. Nurim is a multispanning membrane protein without large hydrophilic domains that is very tightly associated with the nucleus. Unlike the known NE membrane proteins, it is neither associated with nuclear pores, nor targeted like lamin-associated membrane proteins. Thus, nurim is a new type of NE membrane protein that is localized to the NE by a distinct mechanism.
Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA.
M M
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Rolls
P A
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Stein
S S
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Taylor
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Ha
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McKeon
T A
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Rapoport
D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D002460:Cell Line; D002467:Cell Nucleus / Q000737:chemistry; D003001:Cloning, Molecular / Q000379:methods*; D004721:Endoplasmic Reticulum / Q000737:chemistry; D005453:Fluorescence; D015723:Gene Library; D049452:Green Fluorescent Proteins; D006801:Humans; D034882:Lamins; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D008565:Membrane Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009685:Nuclear Envelope / Q000737:chemistry*; D009687:Nuclear Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D012995:Solubility; D013347:Subcellular Fractions / Q000737:chemistry
D034882:Lamins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; C120443:nurim; D049452:Green Fluorescent Proteins