A small ubiquitin-related polypeptide involved in targeting RanGAP1 to nuclear pore complex protein RanBP2

Cell. 1997 Jan 10;88(1):97-107. doi: 10.1016/s0092-8674(00)81862-0.


We have found that the mammalian Ran GTPase-activating protein RanGAP1 is highly concentrated at the cytoplasmic periphery of the nuclear pore complex (NPC), where it associates with the 358-kDa Ran-GTP-binding protein RanBP2. This interaction requires the ATP-dependent posttranslational conjugation of RanGAP1 with SUMO-1 (for small ubiquitin-related modifier), a novel protein of 101 amino acids that contains low but significant homology to ubiquitin. SUMO-1 appears to represent the prototype for a novel family of ubiquitin-related protein modifiers. Inhibition of nuclear protein import resulting from antibodies directed at NPC-associated RanGAP1 cannot be overcome by soluble cytosolic RanGAP1, indicating that GTP hydrolysis by Ran at RanBP2 is required for nuclear protein import.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 3T3 Cells
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Biological Transport
  • Cell Line
  • Cell Nucleus / metabolism*
  • DNA, Complementary / genetics
  • DNA-Binding Proteins / metabolism*
  • GTPase-Activating Proteins*
  • HeLa Cells
  • Humans
  • Mice
  • Molecular Chaperones
  • Molecular Sequence Data
  • Molecular Weight
  • Nuclear Envelope / chemistry
  • Nuclear Envelope / metabolism
  • Nuclear Pore Complex Proteins*
  • Nuclear Proteins / metabolism*
  • Rats
  • SUMO-1 Protein
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Ubiquitins / genetics
  • Ubiquitins / isolation & purification
  • Ubiquitins / metabolism*


  • DNA, Complementary
  • DNA-Binding Proteins
  • GTPase-Activating Proteins
  • Molecular Chaperones
  • Nuclear Pore Complex Proteins
  • Nuclear Proteins
  • RANGAP1 protein, human
  • SUMO-1 Protein
  • Ubiquitins
  • ran-binding protein 2

Associated data

  • GENBANK/U67122