Long Unfolded Linkers Facilitate Membrane Protein Import Through the Nuclear Pore Complex

Natively unfolded linkers facilitate nuclear membrane protein import. Active nuclear import of soluble cargo involves transport factors that shuttle cargo through the nuclear pore complex (NPC) by binding to phenylalanine-glycine (FG) domains. How nuclear membrane proteins cross through the NPC to reach the inner membrane is presently unclear. We found that at least a 120-residue-long intrinsically disordered linker was required for the import of membrane proteins carrying a nuclear localization signal for the transport factor karyopherin-α. We propose an import mechanism for membrane proteins in which an unfolded linker slices through the NPC scaffold to enable binding between the transport factor and the FG domains in the center of the NPC.

[1]  References , 1971 .

[2]  Ronald A. Milligan,et al.  Architecture and design of the nuclear pore complex , 1992, Cell.

[3]  H. Worman,et al.  Signals and structural features involved in integral membrane protein targeting to the inner nuclear membrane , 1995, The Journal of cell biology.

[4]  Howard J. Worman,et al.  Nuclear Membrane Dynamics and Reassembly in Living Cells: Targeting of an Inner Nuclear Membrane Protein in Interphase and Mitosis , 1997, The Journal of cell biology.

[5]  C. Akey,et al.  Three-dimensional architecture of the isolated yeast nuclear pore complex: functional and evolutionary implications. , 1998, Molecular cell.

[6]  J. Lippincott-Schwartz,et al.  Intracellular trafficking of emerin, the Emery-Dreifuss muscular dystrophy protein. , 1999, Journal of cell science.

[7]  B. Chait,et al.  The Yeast Nuclear Pore Complex: Composition, Architecture, and Transport Mechanism , 2000 .

[8]  S. Bailer,et al.  The Nsp1p Carboxy-Terminal Domain Is Organized into Functionally Distinct Coiled-Coil Regions Required for Assembly of Nucleoporin Subcomplexes and Nucleocytoplasmic Transport , 2001, Molecular and Cellular Biology.

[9]  Wei Wu,et al.  Intracellular trafficking of MAN1, an integral protein of the nuclear envelope inner membrane. , 2002, Journal of cell science.

[10]  E. C. Schirmer,et al.  Energy- and temperature-dependent transport of integral proteins to the inner nuclear membrane via the nuclear pore , 2004, The Journal of cell biology.

[11]  D. Goldfarb,et al.  Minimal nuclear pore complexes define FG repeat domains essential for transport , 2004, Nature Cell Biology.

[12]  G. Blobel,et al.  Karyopherin-mediated import of integral inner nuclear membrane proteins , 2006, Nature.

[13]  Ralf P. Richter,et al.  FG-Rich Repeats of Nuclear Pore Proteins Form a Three-Dimensional Meshwork with Hydrogel-Like Properties , 2006, Science.

[14]  B. Chait,et al.  The molecular architecture of the nuclear pore complex , 2007, Nature.

[15]  G. Blobel,et al.  Highway to the inner nuclear membrane: rules for the road , 2007, Nature Reviews Molecular Cell Biology.

[16]  Ed Hurt,et al.  Structural basis of the nic96 subcomplex organization in the nuclear pore channel. , 2008, Molecular cell.

[17]  U. K. Laemmli,et al.  The anchor-away technique: rapid, conditional establishment of yeast mutant phenotypes. , 2008, Molecular cell.

[18]  E. C. Schirmer,et al.  Inner nuclear membrane protein transport is mediated by multiple mechanisms. , 2008, Biochemical Society transactions.

[19]  R. Peters.  Translocation through the nuclear pore: Kaps pave the way , 2009, BioEssays : news and reviews in molecular, cellular and developmental biology.

[20]  O. Medalia,et al.  Structural analysis of a metazoan nuclear pore complex reveals a fused concentric ring architecture. , 2010, Journal of molecular biology.

[21]  D. Kavanagh,et al.  Cell-specific and lamin-dependent targeting of novel transmembrane proteins in the nuclear envelope , 2010, Cellular and Molecular Life Sciences.

[22]  M. Rout,et al.  The nuclear pore complex and nuclear transport. , 2010, Cold Spring Harbor perspectives in biology.

[23]  Andrea Rothballer,et al.  A classical NLS and the SUN domain contribute to the targeting of SUN2 to the inner nuclear membrane , 2010, The EMBO journal.