Theerthagiri G, Eisenhardt N, Schwarz H, Antonin W. The nucleoporin Nup188 controls passage of membrane proteins across the nuclear pore complex.
ACTA ACUST UNITED AC 2010;
189:1129-42. [PMID:
20566687 PMCID:
PMC2894445 DOI:
10.1083/jcb.200912045]
[Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Depletion of the Nup188–Nup93 nuclear pore complex results in enlarged nuclei due to unrestricted protein import.
All transport across the nuclear envelope (NE) is mediated by nuclear pore complexes (NPCs). Despite their enormous size, ∼60 MD in vertebrates, they are comprised of only ∼30 distinct proteins (nucleoporins or Nups), many of which form subcomplexes that act as building blocks for NPC assembly. One of these evolutionarily conserved subcomplexes, the Nup93 complex, is a major structural component linking the NPC to the membranes of the NE. Using in vitro nuclear assembly assays, we show that two components of the Nup93 complex, Nup188 and Nup205, are dispensable for NPC formation. However, nuclei lacking Nup188 increase in size by several fold compared with wild type. We demonstrate that this phenotype is caused by an accelerated translocation of integral membrane proteins through NPCs, suggesting that Nup188 confines the passage of membrane proteins and is thus crucial for the homeostasis of the different nuclear membranes.
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