The mRNA Export Factor Human Gle1 Interacts with the Nuclear Pore Complex Protein Nup155

Abstract

The protein Gle1 is required for export of mRNAs from the nucleus to the cytoplasm in both lower and higher eukaryotic cells. In human (h) cells, shuttling of hGle1 between the nucleus and cytoplasm is essential for bulk mRNA export. To date, no hGle1-interacting proteins have been reported and the mechanism by which hGle1 interacts with the nuclear pore complex (NPC) and mediates export is unknown. To identify proteins that can interact with hGle1, a genome-wide yeast two-hybrid screen was performed. Three potential hGle1-interacting partners were isolated, including clones encoding the C-terminal region of the NPC protein hNup155. This interaction between hGle1 and full-length hNup155 was confirmed in vitro, and deletion analysis identified the N-terminal 29 residues of hGle1 as the hNup155-binding domain. Experiments in HeLa cells confirmed that the nuclear rim localization of the major hGle1 protein variant (hGle1B) was dependent on the presence of these 29 N-terminal residues. This suggests that this domain of hGle1 is necessary for targeting to the NPC. This work also characterizes the first domain in hNup155, a 177 C-terminal amino acid span that binds to hGle1. The mutual interaction between hGle1 and the symmetrically distributed nuclear pore protein Nup155 suggests a model in which hGle1's association with hNup155 may represent a step in the Gle1-mediated mRNA export pathway. Molecular & Cellular Proteomics 3:145-155, 2004.

Nuclear Export of the Yeast mRNA-binding Protein Nab2 Is Linked to a Direct Interaction with Gfd1 and to Gle1 Function

“…This is based on Mex67/Tap/NXF1 nucleocytoplasmic shuttling and essential interactions with both the RNA-bound Yra1 and nucleoporins. The studies in this paper, combined with previous work, have now linked Gle1 both with an RNA-bound protein (Nab2) and nucleoporins (36,40,46,47,48,58) and have shown Gle1 shuttling or having access to both NPC faces (2,49). Thus, Gle1 is also positioned to play an active role in the translocation mechanism.…”

“…The ability of yeast-human Gle1 chimera proteins to complement gle1 mutant cells suggests that the pathways may be functionally conserved (56). Four putative functional domains have been identified in hGle1 (49,57,58). Both the N-and C-terminal domains are required for NPC localization (49,58).…”

“…Four putative functional domains have been identified in hGle1 (49,57,58). Both the N-and C-terminal domains are required for NPC localization (49,58). In addition, there is a coiled-coil domain and a region required for nucleocytoplasmic shuttling (49).…”

“…In addition, there is a coiled-coil domain and a region required for nucleocytoplasmic shuttling (49). Thus far, the only binding partner identified for hGle1 is the NPC-localized hNup155 (58). If the yeast and human pathways are analogous, adaptor proteins similar to Gfd1 could facilitate interactions between hGle1 and shuttling hnRNPs in vertebrate cells.…”

Deficiency in the mRNA export mediator Gle1 impairs Schwann cell development in the zebrafish embryo

“…GLE1-002 mRNA, which produces the 698 amino acid GLE1B peptide, is reported to be expressed about a thousand times more than the GLE1-001 mRNA encoding GLE1A in HeLa cells and its product dominates the intracellular localization profile (Kendirgi et al, 2003). The GLE1 protein has nuclear pore complex (NPC) targeting, coiled-coil, nuclear shuttling and nuclear rim targeting domains (Rayala et al, 2004, Kendirgi et al, 2005, Nousiainen et al, 2008. It 4 has been shown to have several essential roles in vital cellular processes such as mRNA export, translation initiation and translation termination.…”