High impact information on NUP133

• Sir4(PAD)-mediated tethering requires either the Ku complex or Esc1, an acidic protein that is localized to the inner face of the nuclear envelope even in the absence of Ku, Sir4 or Nup133 [1].
• Taken together, our data document that the Nup84p-Nup133p complex self-assembles in a modular concept from distinct smaller nucleoporin construction sets [2].
• Under these conditions, the use of GFP-Nup133p and GFP-Nup49p fusion proteins revealed that Nup133p can be rapidly targeted to the clustered nuclear pores, where its amino-terminal domain is required to promote the redistribution of preexisting NPCs [3].
• To try to uncouple Nup133p-induced NPC redistribution from successive nuclear divisions and nuclear pore biogenesis, we devised an assay based on the formation of heterokaryons between nup133- mutants and cells either expressing or overexpressing Nup133p [3].
• The ORF predicts a protein with a calculated molecular mass of 120.5 kD containing two leucine zipper motifs, a short coiled-coil region and limited primary sequence similarity to Nup133p [4].

Biological context of NUP133

• NUP133 is not an essential gene, but cells in which NUP133 is disrupted grow slowly at permissive temperatures and stop growing at 37 degrees C. Concomitant with the growth inhibition, nup133- cells accumulate poly(A)+ RNA inside the nucleus whereas nuclear import of a karyophilic reporter protein is not altered [5].
• Due to its coenrichment with NPCs during cell fractionation and the phenotype observed in the disrupted strain, we propose to term the gene encoding this protein NUP133 [6].
• A novel nuclear pore protein Nup133p with distinct roles in poly(A)+ RNA transport and nuclear pore distribution [5].

Anatomical context of NUP133

• Disruption of the nucleoporin gene NUP133 results in clustering of nuclear pore complexes [6].
• Similar NPC clustering was seen in mutant cells cultured at temperatures between 15 degrees C and 37 degrees C. The RAT3 gene encodes an 1157-amino acid protein without similarity to other known proteins [7].

Physical interactions of NUP133

• More interestingly, we demonstrate that the Nup84p complex contains Nup133p as a subunit and binds to the FG repeat regions of Nups directly via the Nup85p subunit [8].

Other interactions of NUP133

• Strains mutant for Nup133p or Nsp1p accumulated lower levels of several unspliced pre-tRNAs [9].
• In nup133- dividing cells that display a constitutive nuclear pore clustering, in vivo analysis of GFP-Nup49p localization revealed changes in the distribution of nuclear pore complex (NPC) clusters [3].

References