The nucleoporins Nup170p and Nup157p are essential for nuclear pore complex assembly.
We have established that two homologous nucleoporins, Nup170p and Nup157p, play an essential role in the formation of nuclear pore complexes (NPCs) in Saccharomyces cerevisiae. By regulating their synthesis, we showed that the loss of these nucleoporins triggers a decrease in NPCs caused by a halt in new NPC assembly. Preexisting NPCs are ultimately lost by dilution as cells grow, causing the inhibition of nuclear transport and the loss of viability. Significantly, the loss of Nup170p/Nup157p had distinct effects on the assembly of different architectural components of the NPC. Nucleoporins (nups) positioned on the cytoplasmic face of the NPC rapidly accumulated in cytoplasmic foci. These nup complexes could be recruited into new NPCs after reinitiation of Nup170p synthesis, and may represent a physiological intermediate. Loss of Nup170p/Nup157p also caused core and nucleoplasmically positioned nups to accumulate in NPC-like structures adjacent to the inner nuclear membrane, which suggests that these nucleoporins are required for formation of the pore membrane and the incorporation of cytoplasmic nups into forming NPCs.
Makio
Tadashi
T
Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada.
Stanton
Leslie H
LH
Lin
Cheng-Chao
CC
Goldfarb
David S
DS
Weis
Karsten
K
Wozniak
Richard W
RW
D021581:Active Transport, Cell Nucleus / Q000235:genetics / Q000502:physiology; D017353:Gene Deletion; D016681:Genome, Fungal; D008715:Methionine / Q000172:deficiency; D009685:Nuclear Envelope / Q000235:genetics / Q000502:physiology; D022022:Nuclear Pore / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D028861:Nuclear Pore Complex Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D011401:Promoter Regions, Genetic; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology*
C097179:NUP157 protein, S cerevisiae; C097178:NUP170 protein, S cerevisiae; D028861:Nuclear Pore Complex Proteins; D029701:Saccharomyces cerevisiae Proteins; D008715:Methionine