Functional association of Sun1 with nuclear pore complexes.
Sun1 and 2 are A-type lamin-binding proteins that, in association with nesprins, form a link between the inner nuclear membranes (INMs) and outer nuclear membranes of mammalian nuclear envelopes. Both immunofluorescence and immunoelectron microscopy reveal that Sun1 but not Sun2 is intimately associated with nuclear pore complexes (NPCs). Topological analyses indicate that Sun1 is a type II integral protein of the INM. Localization of Sun1 to the INM is defined by at least two discrete regions within its nucleoplasmic domain. However, association with NPCs is dependent on the synergy of both nucleoplasmic and lumenal domains. Cells that are either depleted of Sun1 by RNA interference or that overexpress dominant-negative Sun1 fragments exhibit clustering of NPCs. The implication is that Sun1 represents an important determinant of NPC distribution across the nuclear surface.
Liu
Qian
Q
Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32610, USA.
Pante
Nelly
N
Misteli
Tom
T
Elsagga
Mohamed
M
Crisp
Melissa
M
Hodzic
Didier
D
Burke
Brian
B
Roux
Kyle J
KJ
D020816:Amino Acid Motifs; D000818:Animals; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009685:Nuclear Envelope / Q000378:metabolism*; D022022:Nuclear Pore / Q000378:metabolism*; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020836:Protein Structure, Quaternary; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; C506117:SUN1 protein, human; C413025:SUN2 protein, human