Starting in 1990, researchers took advantage of yeast genetic screens as well as cross-reacting monoclonal antibodies made against vertebrate NPCs to identify the first NPC components (termed nucleoporins or "Nups") in yeast.
Transport receptors of the importin family bind a large proportion of nucleoporins and have been proposed to regulate the post-mitotic formation of NPCs by blocking the relevant interactions between NPC components (Harel et al. 2003; Walther et al. 2003b).
However, Nup153 and Tpr are dynamic NPC components, and in addition to being part of NPCs, they are associated with active chromatin within the nucleus (Vaquerizas et al. 2010).
Given the importance of Hmt1-mediated methylation of hnRNPs for efficient hnRNP nuclear export [44], [64], and the critical role of the NPC in mRNA export, we next examined whether Ccr4-Not associations with hnRNPs and NPC components might have functional implications for mRNA nuclear export.
Firstly, we find that under similar experimental cross-linking conditions, OST-tagged progerin does not pull down NPC components despite the presence of lamin A, which is known to interact with NPCs (Kubben et al. 2010).
As Mlp1, Mlp2, and Nup60 are all nuclear NPC components, their co-purification with Ccr4-Not subunits suggests that interactions between Ccr4-Not and the NPC may occur on the nuclear face of the NPC, a subnuclear domain that has critical roles in mRNA export [4], [5].
In many cases, these functions are positionally linked to NPCs and the extended structures emanating from the nuclear basket, but it is becoming increasingly clear that NPC components exert control far beyond this nuclear microenvironment.
