Human GTPases associate with RNA polymerase II to mediate its nuclear import

Clément Carré, Ramin Shiekhattar

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Small GTPases share a biochemical mechanism and act as binary molecular switches. One important function of small GTPases in the cell is nucleocytoplasmic transport of both proteins and RNA. Here, we show the stable association of human GPN1 and GPN3, small GTPases related to Ran, with RNA polymerase II (RNAPII) isolated from either the cytoplasmic or nuclear fraction. GPN1 and GPN3 directly interact with RNAPII subunit 7 (RPB7)/RPB4 and the C-terminal domain (CTD) of RNAPII. Depletion of GPN1 or GPN3 using small interfering RNAs led to decreased RNAPII levels in the nucleus and an accumulation of this enzyme in the cytoplasm of human cells. Furthermore, isolation of a GPN1/GPN3/RNAPII complex from stable cell lines expressing a dominant negative GPN1 harboring mutations in the GTP-binding pocket demonstrated a role for these proteins in nuclear import of RNAPII. Thus, GPN1/GPN3 define a new family of small GTPases that are specialized for the transport of RNA polymerase II into the nucleus.

Original languageEnglish (US)
Pages (from-to)3953-3962
Number of pages10
JournalMolecular and cellular biology
Issue number19
StatePublished - Oct 2011
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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