The FG-repeat asymmetry of the nuclear pore complex is dispensable for bulk nucleocytoplasmic transport in vivo.
Nucleocytoplasmic transport occurs through gigantic proteinaceous channels called nuclear pore complexes (NPCs). Translocation through the NPC is exquisitely selective and is mediated by interactions between soluble transport carriers and insoluble NPC proteins that contain phenylalanine-glycine (FG) repeats. Although most FG nucleoporins (Nups) are organized symmetrically about the planar axis of the nuclear envelope, very few localize exclusively to one side of the NPC. We constructed Saccharomyces cerevisiae mutants with asymmetric FG repeats either deleted or swapped to generate NPCs with inverted FG asymmetry. The mutant Nups localize properly within the NPC and exhibit exchanged binding specificity for the export factor Xpo1. Surprisingly, we were unable to detect any defects in the Kap95, Kap121, Xpo1, or mRNA transport pathways in cells expressing the mutant FG Nups. These findings suggest that the biased distribution of FG repeats is not required for major nucleocytoplasmic trafficking events across the NPC.
Zeitler
Bryan
B
Division of Cell and Developmental Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
Weis
Karsten
K
D021581:Active Transport, Cell Nucleus / Q000235:genetics; D020816:Amino Acid Motifs / Q000235:genetics; D001665:Binding Sites / Q000235:genetics; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism*; D005998:Glycine / Q000378:metabolism; D028884:Karyopherins / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D022022:Nuclear Pore / Q000235:genetics / Q000378:metabolism*; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism*; D010649:Phenylalanine / Q000235:genetics; D011485:Protein Binding / Q000235:genetics; D021381:Protein Transport / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D018911:Trinucleotide Repeats / Q000235:genetics; D028961:beta Karyopherins / Q000235:genetics / Q000378:metabolism; D000097606:Exportin 1 Protein
D005998:Glycine; D028884:Karyopherins; D026901:Membrane Transport Proteins; D028861:Nuclear Pore Complex Proteins; D010649:Phenylalanine; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D029701:Saccharomyces cerevisiae Proteins; D028961:beta Karyopherins; D000097606:Exportin 1 Protein; C483822:PSE1 protein, S cerevisiae