The BioGRID | PUBLICATION VIEW

	J. Cell Biol. Aug (2007); 178(5):813-27
A nuclear envelope protein linking nuclear pore basket assembly, SUMO protease regulation, and mRNA surveillance-
Lewis A, Felberbaum R, Hochstrasser M
Departments of Cell Biology, Yale University, New Haven, CT 06520, USA-
Abstract: The nuclear pore complex -NPC- is both the major conduit for nucleocytoplasmic trafficking and a platform for organizing macromolecules at the nuclear envelope- We report that yeast Esc1, a non-NPC nuclear envelope protein, is required both for proper assembly of the nuclear basket, a structure extending into the nucleus from the NPC, and for normal NPC localization of the Ulp1 SUMO protease- In esc1Delta cells, Ulp1 and nuclear basket components Nup60 and Mlp1 no longer distribute broadly around the nuclear periphery, but co-localize in a small number of dense-staining perinuclear foci- Loss of Esc1 -or Nup60- alters SUMO conjugate accumulation and enhances ulp1 mutant defects- Similar to previous findings with Mlp1, both Esc1 and Ulp1 help retain unspliced pre-mRNAs in the nucleus- Therefore, these proteins are essential for proper nuclear basket function, which includes mRNA surveillance and regulation of SUMO protein dynamics- The results raise the possibility that NPC-localized protein desumoylation may be a key regulatory event preventing inappropriate pre-mRNA export-
[PUBMED: 17724121]