My research concentrates on understanding how key cellular functions are generated in terms of the molecules involved and the interactions between them. I use a combination of structural, cellular and protein engineering methods to determine the structure of key proteins, how they interact, and how these interactions generate function. Structures are being determined using X-ray crystallography and NMR; interactions defined using biochemical and EM methods; and protein engineering is being used to produce modified proteins and constructs. In addition, in vivo and in vitro assay systems are being used to investigate the Cell Biology of these systems. Overall, I aim to integrate the structural and biochemical data in order to understand the machinery and mechanism of key cellular processes at the molecular level.
My research is currently concentrating on investigating in detail two specific questions: (i) the molecular mechanism of nucleocytoplasmic transport, especially that of mRNA nuclear export; (ii) the role of nuclear trafficking components in organizing the gene expression machinery.
Proteins and nucleic acids are transported across the nuclear envelope through nuclear pore complexes (NPCs). These are huge macromolecular assemblies about 1200 A in diameter that perforate the double membrane of the nuclear envelope and which have a mass of about 125,000,000 Da (about 30 times that of a ribosome). NPCs are probably constructed from about 30 different proteins (nucleoporins) and many of these have now been cloned, sequenced and expressed. Nucleoporins, such as vertebrate p62 and yeast Nsp1p, frequently contain repeating sequence motifs based on Phe-rich core domains (such as FxFG or GLFG) joined by hydrophilic linkers with varying lengths and sequences. Except for mRNA, nuclear import and export are both mediated by soluble carrier molecules that are members of the importin-b superfamily. These carrier molecules bind cargo in one compartment and, after carrying it through the NPCs, release it in the other compartment, after which the carrier molecules have to be recycled. In addition to the carriers, trafficking also requires the Ras-family GTPase Ran and nuclear transport factor 2(NTF2). The nuclear export of mRNA is instead mediated by the Mex67:Mtr2 transport factor (TAP:P15 or Nxf1:Nxt1 in metazoans) and is coupled to preceding steps in the gene expression pathway such as splicing and cleavage/polyadenylation.
My group has determined the structures of a number of transport factors alone or in complex with other components of the trafficking machinery. This information has been integrated with cellular and molecular interaction information to build up a detailed picture of the nuclear protein import pathway. Current work is concentrating on mRNA export and how it is integrated with the nuclear steps in the gene expression pathway.
E.Conti, C.W.Müller & M.Stewart. (2006). Karyopherin flexibility in nucleocytoplasmic transport. Curr. Opin. Struct. Biol. 16:237-244.
A.Lange, R.E.Mills, C.J.Lange, M.Stewart, S.E.Devine & A.H.Corbett. (2007). Classical nuclear localization signals: Definition, function, and interaction with importin-alpha. J. Biol. Chem. 282:5101-5105.
M.Stewart. (2007). Molecular mechanism of the nuclear protein import cycle. Nature Rev. Mol. Cell. Biol. 8:195-208.
M.Stewart. (2007). Ratcheting mRNA out of the nucleus. Molecular Cell, 25:327-330.
M.Stewart. (2010). Nuclear export of messengerRNA. Trends Biochem. Sci. doi: 10.1016/j.tibs2010.07.001.
E.Valkov, J.C.Dean, D.Jani, S.I.Kuhlmann & M.Stewart (2012). Structural basis for the assembly and disassembly of mRNA nuclear export complexes. BBA Gene Reg. Mech. doi:10.1016/j.bbagrm.2012.02.017.
Research papers:R.Bayliss, T.Littlewood & M.Stewart. (2000). Structural basis for the interaction between importin-beta and nucleoporin FxFG repeats in nuclear trafficking. Cell, 102:99-108.
R.P.Grant, E.Hurt, D.Neuhaus & M.Stewart. (2002). Structure of the C-terminal FG-nucleoporin binding domain of Tap/NXF1. Nature Struct. Biol. 9:247-251.
R.Bayliss, T.Littlewood, L.A.Strawn, S.R.Wente & M.Stewart. (2002). GLFG and FxFG nucleoporins bind to overlapping sites on importin-beta. J. Biol. Chem. 277:50597-50606.
R.Bayliss, S.W.Leung, R.P.Baker, B.B.Quimby, A.H.Corbett & M.Stewart. (2002). Structural basis for the interaction between nuclear transport factor 2 (NTF2) and nucleoporin FxFG repeats. EMBO J. 21:2843-2853.
Y.Matsuura, A.Lange, M.Harriman, A.H.Corbett & M.Stewart. (2003). Structural basis for the function of Nup2p in cargo release and karyopherin recycling in nuclear import. EMBO J. 22:5358-5369.
Y.Matsuura & M.Stewart. (2004). Structural basis for the assembly of a nuclear export complex. Nature, 432:872-877.
S.M.Liu & M.Stewart. (2005). Structural basis of the high-affinity binding of nucleoporin Nup1p to the Saccharomyces cerevisiae importin-beta homologue, Kap95p. J. Mol. Biol. 349:515-525.
S.J.Lee, Y.Matsuura, S.M.Liu & M.Stewart. (2005). Structural basis for nuclear import complex disassembly by RanGTP. Nature, 435:693-696.
Y.Matsuura & M.Stewart. (2005). Nup50/Npap60 function in nuclear protein import complex disassembly and importin recycling. EMBO J. 24:3681-3689.
M.L.Cutress, H.C.Whitaker, I.G.Mills, M.Stewart & D.E.Neal. (2008). Structural basis for the nuclear import of the androgen receptor. J. Cell Sci. 121:957-968.
M.Fasken, M.Stewart & A.H.Corbett. (2008). Functional significance of the interaction between the mRNA-binding protein, Nab2, and the nuclear pore-associated protein, Mlp1, in mRNA export. J. Biol. Chem. 283:27130-27143.
C.Zheng, M.B.Faskin, N.J.Marshall, C.Brockmann, M.E.Rubinson, S.R.Wente, A.H.Corbett & M.Stewart. (2010). Structural basis for the function of the Saccharomyces cerevisiae Gfd1 protein in mRNA nuclear export. J. Biol. Chem. 285:20704-20715.
J.K.Forwood, A.Lange, U.Zachariae, M.Marfori, C.Preast, H.Grubmüller, M.Stewart, A.H.Corbett & B.Kobe. (2010). Quantitative analysis of importin-b flexibility: paradigm for solenoid protein structures. Structure, 18:1171-1183.
A.Fox, D.Ciziene S.H.McLaughlin & M.Stewart. (2011). Electrostatic interactions involving the extreme C-terminus of nuclear export factor CRM1 modulate its affinity for cargo. J. Biol. Chem. 286:29325-29335.
C.Brockmann, S.Soucek , S.Kuhlmann, S.M.Kelly, J.-C.Yang, N.Inglesias, F.Stutz, A.H.Corbett, D.Neuhaus and M.Stewart. (2012). Structural basis for the recognition of polyadenosine RNA by a tandem Zn finger repeat in Nab2 and its function in mRNA nuclear export. Structure, 20:1007-1018.
C.Sun, G.Fu, D.Ciziene, M.Stewart & S.M.Musser. (2013). Choreography of Importin ?/CAS complex assembly and disassembly at nuclear pores. Proc. Natl. Acad. Sci., USA. 110:E1584-1593.
S.I.Kuhlmann, E.Valkov & M.Stewart. (2014). Structural basis for the molecular recognition of polyadenosine RNA by Nab2 Zn fingers. Nucleic Acids Res. 42:672-680.
S.Aibara, E.Valkov, M.H.Lamers & M.Stewart. (2015). Domain organization within thenuclear export factor Mex67:Mtr2 generates an extended mRNA binding surface. Nucleic Acids Res. 43:1927-1936. doi: 10.1093/nar/gkvo30.
S.Aibara, J.Katahira, E.Valkov & M.Stewart. (2015). The principal mRNA export factor NXF1:NXT1 forms a symmetric binding platform for retroviral RNA export. Nucleic Acids Res. 43:1883-1893. doi: 10.1093/nar/gkvo32.
R.S.Wagner, L.E.Kapinos, N.J.Marshall, M.Stewart & R.Y.H.Lim. (2015). Promiscuous Binding of Karyopherinβ1 to FG Nucleoporins Contributes to Nuclear Pore Barrier Function and Fast Transport Kinetics of NTF2. Biophys. J. 108:918-927.
R.S.Holvey, E.Valkov, D.Neal, M.Stewart & C.Abell. (2015). Selective targeting of the TPX2 site of importin-α using fragment-based ligand design. ChemMedChem. 10:1232-1239. doi: 10.1002/cmdc.201500014.
S.Aibara, E.Valkov, M.Lamers, L.Dimitrova, E.Hurt & M.Stewart. (2015). Structural characterization of the principal mRNA export factor Mex67:Mtr2 from C. thermophilum. Acta Cryst. Ser. F. 71:876-888.
R.Zahn, D.Osmanovi?, S.V. Ehret, C.A.Callis, S.Frey, M.Stewart, C.You, D.Görlich, B.W.Hoogenboom & R.P.Richter. (2016). A physical model describing the interaction of a nuclear transport receptor with FG nucleoporin domain assemblies. eLife, 5:e14119, doi: 10.7554/eLife.14119.
M.M.Wiedmann, S.Aibara, D.R.Spring, M.Stewart & J.D.Brenton. (2016). Structural and calorimetric studies demonstrate that the Hepatocyte Nuclear Factor 1β (HNF1β) transcription factor is imported into the nucleus via a monopartite NLS sequence. J. Struct. Biol. 195:273-281 - doi: 10.1016/j.jsb.2016.06.018.
M.M.Wiedmann, Y.S.Tan, Y.Wu, S.Aibara, H.F.Sore, C.S.Verma, M.Stewart, J.D.Brenton & D.R.Spring. (2017). Development of Conformationally Constrained Peptides to Target the Hepatocyte Nuclear Factor 1β – Importin α Protein-Protein Interaction in Ovarian Cancer. Angew. Chemie, 56:524-529. doi: 10.1002/ange.201609427.
S.Aibara, J.M.Gordon, A.Riesterer, S.H.McLaughlin & M.Stewart. (2017). Nab2 dimerization generated by RNA binding contributes to both poly(A) tail length determination and transcript compaction in Saccharomyces cerevisiae. Nucl. Acids Res. 45:1529-1538. doi:10.1093/nar/gkw1224.
Background: The nuclear export of RNAs is a key function in eukaryotic cells and is conveniently considered separately from the transcription and processing steps of the gene expression pathway that precede it. The key events in mRNA export are the formation of export-competent mRNP complexes and in their subsequent disassembly in the cytoplasm after passage through NPCs. Mex67:Mtr2 and Nab2 are central components of mRNA export complex assembly and disassembly. Mex67:Mtr2 is the principal mRNA export factor that has to become incorporated into the mRNP before it can pass through the NPC and which is then removed in the cytoplasm to prevent the return of the mRNA to the nucleus. Together with Mlp1/2, Nab2 is important in determining polyA tail length and is also a component of the surveillance machinery that prevents export of defective mRNA. Nab2 remains bound to the mRNP during export through NPCs and then, on the cytoplasmic face of the NPC, Nab2 recruits Gle1 (using Gfd1 as an adaptor) and initiates mRNP disassembly in conjunction with Dbp5. The goal of this project is to identify the molecular mechanisms involved in these processes.
Formation of export-competent mRNPs in the nucleus is the culmination of this segment of the gene expression pathway and results from a complex series of interactions between components of the transcription, processing and surveillance machinery. These steps ensure that nuclear processing has been completed and that the transport factors necessary for transit through NPCs have been attached. Although the principal mRNA export factor, Mex67:Mtr2, binds both mRNA and Nups, accessory proteins are required both to generate an export-competent mRNP in the nucleus and to disassemble it in the cytoplasm. The RNA-binding proteins Yra1 and Nab2 are key components of both of these processes. In conjunction with nuclear basket proteins Mlp1/2, Nab2 functions in surveillance, becoming attached at a late stage to the export-competent mRNP and accompanying it though NPCs, after which the mRNP is disassembled. The precise mechanism by which mRNP export complexes are disassembled is not known. However, Gle1 and the DEAD-box helicase Dbp5 have been identified as having roles in mRNP export complex disassembly. The participation of DEAD-box helicases in both the assembly and disassembly of the mRNP export complex would be consistent with local remodeling of the structure of the mRNP being important in both the binding and release of Mex67:Mtr2 and Nab2.1.1 Generation of export-competent mRNPs: The Mex67:Mtr2 complex (TAP:P15 in metazoans) is central to the generation of many export-competent mRNPs in the nucleus and its removal in the cytoplasm prevents mRNA returning to the nucleus. Mex67 has four functional domains joined through flexible linkers. There are two C-terminal FG-Nup binding domains and two N-terminal domains associated with RNA and protein interactions. Mex67:Mtr2 is recruited to mRNA using the Yra1 adaptor, a component of the transcription-export (TREX) complex and the exon-junction complex (EJC). The structural basis of the binding of either Yra1 or Mex67 to mRNA has not been established. The EJC, the 5' end, and the 3' cleavage-polyadenylation factor CF1A have all been proposed to be important in positioning Yra1 and/or its metazoan homologue REF/ALY on mRNA. Before mRNA export, Yra1 is removed by the DEAD-box helicase Sub2, another TREX component. Yra1 interacts with CF1A component Pcf11, Sub2, and Mex67 in a mutually exclusive manner, consistent with these binding sites at least partially overlapping. It appears that Yra1 may be initially recruited to the mRNA co-transcriptionally by CF1A, transferred to Sub2 and then to Mex67 before being finally removed. Mutations in Sub2 or the THO complex (the remaining component of TREX) lead to accumulation of stalled mRNP intermediates that are associated with both Nups and polyadenylation factors, consistent with Sub2 function being required to coordinate the acquisition of export competence subsequent to commitment to 3' processing. Sub2 may function by remodeling mRNPs to strengthen the interaction with Mex67:Mtr2 while weakening binding to Yra1. A further checkpoint may involve the Mex67 UBA domain, which is bound by ubiquitinated Hpr1 (a THO complex component) and is only able to bind Nup FG-repeats (and so facilitate passage through NPCs) after deubiquitinylation of Hpr1. After the mature mRNP has moved to the cytoplasmic face of the NPC, Mex67:Mtr2 and Nab2 are removed by the action of Dbp5. This is the terminal step of the thermal ratchet that prevents the return of exported mRNA to the nucleus.
The structure of complexes involving fragments of Pcf11, Yra1, Sub2 and Mex67 is being investigated using crystallography and NMR to define interaction interfaces. These data will then be used to construct specific mutants that alter these interactions to define their role in Mex67 recruitment. The RNA motif(s) recognized by Yra1 and Mex67 are being explored using TAP-tagged pull-downs complemented with CLIP (UV CrossLinking and ImmunoPrecipitation) and SELEX, to monitor direct protein-RNA interactions in vivo and determine the sequence specificity of protein-RNA recognition. These studies are being complemented by developing in vitro systems in which the binding of Yra1 and Mex67:Mtr2 to mRNA and their displacement by Sub2 and Dbp5 can be reconstituted so that the structure of the complexes between mRNA and these factors can be established by crystallography, cryoEM/tomography and NMR.1.2 Function of Nab2: Nab2 is important in polyA tail length determination, in signaling when mRNPs are export-competent, and in increasing the efficiency with which Dbp5 disassembles export complexes. To gain greater insight into this function, protein:protein interactions are being explored between Nab2 and the N-terminal domain with Mlp1 and Gfd1 together with establishing how its Zn finger domain binds to polyA mRNA.Nab2 contains three functional domains. The ~100 residue N-terminal domain, the structure of which my group has determined to 1.8 Å resolution, is central to the interaction of Nab2 with both the surveillance machinery (though its interaction with Mlp1/2) and the disassembly machinery (through its interaction with Gle1 using the Gfd1 adaptor). Nab2 also binds selectively to polyA RNA through its Zn finger domains and this interaction is important in determining polyA tail length and also the compaction of mRNPs needed to facilitate transport through NPCs. When the mRNP reaches the cytoplasm, Nab2 is removed through the action of Dbp5.
I am using crystallography and NMR, complemented by mutagenesis targeted to key surface regions identified in the Nab2 N-terminal domain’s structure together with crosslinking, to establish its interaction interfaces with its partner proteins. NMR and crystallography are also being used to determine the structure of the Nab2 Zn finger domain and define how these fingers bind specifically to polyA mRNA. A crystal structure of fingers 5-7 bound to A11G RNA has been obtained and has identified the role of key aromatic residues and a kew finger Cysteine in the specificity of recognition. This structure has also indicated that Nab2 Zn fingers 5-7 bind to two separate A-rich regions of the RNA to generate a heterotetramer containing two Nab2 and two RNA chains. This dimerization of Nab2 mediated by A-rich RNA offers an explanation of how it impacts on polyA tail length in yeast (because each Nab2 binds 30 As) and also accounts for how, by linking A-rich regions throughout the transcript, Nab2 can mediate compression. Current work is directed towards testing these hypostheses and also exploring the role of metazoan Nab2 homologues in which mutations have been associated with neurological defects.
1.3 Disassembly of mRNP export complexes: The terminal step in the mRNP export thermal ratchet is the removal of factors including Mex67:Mtr2 and Nab2 that is mediated by the DEAD-box helicase Dbp5, the structure of which has been recently determined. In addition to Dbp5, efficient export complex disassembly also requires Gle1 and IP6. Understanding the interactions between Dbp5, Gle1, Nab2, Gfd1 and the cytoplasmic Nups is needed to determine how they act in concert to disassemble mRNP export complexes. Moreover, it is likely that Dbp5 may reverse the remodelling of the complex generated in the nucleus by Sub2.
Initially work is being targeted on the interactions involving Gfd1, taking advantage of results obtained with its complex with Nab2. Mutants are being engineered that can be employed to define the role of each interaction in the disassembly of the mRNP export complex, initially in vitro and then in vivo in yeast.
M.Stewart. (2007). Ratcheting mRNA out of the nucleus. Molecular Cell, 25:327-330.
M.Stewart. (2010). Nuclear export of messengerRNA. Trends Biochem. Sci. doi: 10.1016/j.tibs2010.07.001.
E.Valkov, J.C.Dean, D.Jani, S.I.Kuhlmann & M.Stewart (2012). Structural basis for the assembly and disassembly of mRNA nuclear export complexes. BBA Gene Reg. Mech. doi:10.1016/j.bbagrm.2012.02.017.
Research papers:M.Hobeika, C.Brockmann, N.Iglesias, C.Gwizdek, D.Neuhaus, F.Stutz, M.Stewart, G.Divita & C.Dargemont. (2007). Coordination of Hpr1 and ubiquitin binding by the UBA domain of the mRNA export factor Mex67. Mol. Biol. Cell, 18:2561-2568.
R.P.Grant, N.J.Marshall, J-C.Yang, M.B.Fasken, S.M.Kelly, M.T.Harreman, D.Neuhaus, A.H.Corbett & M.Stewart. (2008). Structure of the N-terminal Mlp1-binding domain of Nab2. J. Mol. Biol. 376:1048-1059.
M.Hobeika, C.Brockmann, D.Neuhaus, G.Divita, M.Stewart & C.Dargemont. (2009). Binding of Hpr1 and ubiquitin to the UBA domain of Mex67 modulates its interaction with nucleoporin FxFG repeats. J. Biol. Chem. 284:17575-17583.
M.Fasken, M.Stewart & A.H.Corbett. (2008). Functional significance of the interaction between the mRNA-binding protein, Nab2, and the nuclear pore-associated protein, Mlp1, in mRNA export. J. Biol. Chem. 283:27130-27143.
C.Zheng, M.B.Faskin, N.J.Marshall, C.Brockmann, M.E.Rubinson, S.R.Wente, A.H.Corbett & M.Stewart. (2010). Structural basis for the function of the Saccharomyces cerevisiae Gfd1 protein in mRNA nuclear export. J. Biol. Chem. 285:20704-20715.
C.Brockmann, S.Soucek , S.Kuhlmann, S.M.Kelly, J.-C.Yang, N.Inglesias, F.Stutz, A.H.Corbett, D.Neuhaus and M.Stewart. (2012). Structural basis for the recognition of polyadenosine RNA by a tandem Zn finger repeat in Nab2 and its function in mRNA nuclear export. Structure, 20:1007-1018.
S.I.Kuhlmann, E.Valkov & M.Stewart. (2014). Structural basis for the molecular recognition of polyadenosine RNA by Nab2 Zn fingers. Nucleic Acids Res. 42:672-680.
D.Jani, E.Valkov & M.Stewart. (2014). Structural basis for the nuclear pore binding of the TREX-2 transcription-export complex and its function in mRNA nuclear export and re-positioning of active GAL1. Nucleic Acids Res. 42:6686-6697. doi:10.1093/nar/gku252.
S.Aibara, E.Valkov, M.H.Lamers & M.Stewart. (2015). Domain organization within thenuclear export factor Mex67:Mtr2 generates an extended mRNA binding surface. Nucleic Acids Res. 43:1927-1936. doi: 10.1093/nar/gkvo30.
S.Aibara, J.Katahira, E.Valkov & M.Stewart. (2015). The principal mRNA export factor NXF1:NXT1 forms a symmetric binding platform for retroviral RNA export. Nucleic Acids Res. 43:1883-1893. doi: 10.1093/nar/gkvo32.
S.Aibara, E.Valkov, M.Lamers, L.Dimitrova, E.Hurt & M.Stewart. (2015). Structural characterization of the principal mRNA export factor Mex67:Mtr2 from C. thermophilum. Acta Cryst. Ser. F. 71:876-888.
S.Aibara, J.M.Gordon, A.Riesterer, S.H.McLaughlin & M.Stewart. (2017). Nab2 dimerization generated by RNA binding contributes to both poly(A) tail length determination and transcript compaction in Saccharomyces cerevisiae. Nucl. Acids Res. 45:1529-1538. doi:10.1093/nar/gkw1224.
Background: The integration of transcription, splicing, processing, and nuclear export in yeast is mediated by the TREX and TREX-2 complexes. TREX-2 is based on Sac3 and functions as an interaction platform, linking the SAGA complex to NPCs. SAGA and TREX-2 have physical and functional links. Significantly, deletions of components of SAGA, TREX-2 or Nup1 cause defects in the movement of GAL genes upon transcriptional activation to the nuclear periphery, a process fundamental to gene-gating. In addition, the structure of the Thp1:Sem1:Sac3 complex has indicated that TREX-2 can bind directly to nucleic acids.
Current research is extending previous work from my group that established the structure of the Sus1:Cdc31:Sac3, Sus1:Cdc31:Sac3:Nup1, and Thp1:Sac3:Sem1 complexes and aims to define how TREX-2 interacts with NPCs, Mex67:Mtr2, Thp1 and the SAGA and THO complexes to integrate mRNA export with preceding steps in the gene expression pathway in both yeast and metazoans. A combination of molecular methods (ChIP, SELEX, crosslinking) is also being used to define the way in which TREX-2 binds to nucleic acids and the role of these interactions in gene gating.
Sac3 interactions with Mex67:Mtr2 and the SAGA and THO complexes: In addition to binding Sus1 and Cdc31, Sac3 also binds the THO complex (via Thp1), the SAGA complex, and Mex67:Mtr2. A combination of proteolysis, deletion fragments and TAP-tagged pull-downs is being employed to define the regions on Sac3 that bind to Thp1 and Mex67:Mtr2. The structure of the interaction interface will then be determined using crystallography and NMR was appropriate. Mutants that alter these interactions will then be engineered and tested in vitro and in vivo to establish the role of each interaction in integration of the gene expression pathway.
Nucleic acid binding by TREX-2: Structure-guided mutagenesis has identified a putative nucleic acid binding region on the Thp1:Sem1:Sac3 complex, but the structural basis of this interaction and the details of the molecular recognition involved remain to be established. My lab is defining the sequence specificity of this interaction and aims to generate crystals of complexes between TREX-2 and nucleic acids to define the precise role of this interaction in gene gating and transcriptional memory.
Sus1, Cdc31 and Sac3 analogues in metazoan mRNA export: The role of Sus1, Cdc31 and Sac3 homologues (CD6, centrin 2 and GANP, respectively) in metazoan gene expression has been explored in collaboration with Ron Laskey and Vi Wickramasinghe (MRC-Hutchison Centre) and is now being extended to explore its role in neurological disorders such as ALS.
D.Jani, S.Lutz, N.J.Marshall, T.Fischer, A.Köhler, A.M.Ellisdon, E.Hurt & M.Stewart. (2009). Sus1, Cdc31 and the Sac3 CID region form a conserved interaction platform that promotes nuclear pore association and mRNA export. Molecular Cell, 33:727-737.
C.Klöckner, M.Schneider, S.Lutz, D.Jani, D.Kressler, M.Stewart, E.Hurt & A.Köhler. (2009). Mutational uncoupling of Sus1's role in Histone H2B deubiquitination and NPC-targeting of an mRNA export complex. J. Biol. Chem. 284:12049-12056.
V.O.Wickramasinghe, P.I.A.McMurtrie, A.D.Mills, R.Andrews, P.Ellis, Y.Takei, S.Penrhyn-Lowe, Y.Amagase, S.Main, J.Marr, C.Langford, M.Stewart & R.A.Laskey. (2010). Mammalian mRNA export requires GANP. Curr. Biol. 20:25-31.
A.M.Ellisdon, D.Jani, A.Köhler, E.Hurt & M.Stewart. (2010). Structural basis for the interaction between yeast SAGA complex components Sgf11 and Sus1. J. Biol. Chem. 285:3850-3856.
A.M.Ellisdon, L.Dimitrova, E.Hurt & M.Stewart. (2012). Structural basis for the assembly and nucleic acid binding of the TREX-2 transcription-export complex. Nature Struct. Mol. Biol. 19:328-336.
D.Jani, S.Lutz, E.Hurt, R.A.Laskey, M.Stewart & V.O.Wickramasinghe. (2012). Function of the ENY2:Centrin2:GANP complex in mRNA export. Nucleic Acid Res. (in press - doi 10.1093/nar/gks059).
D.Jani, S.Lutz, E.Hurt, R.A.Laskey, M.Stewart & V.O.Wickramasinghe. (2012). Functional and structural characterization of the mammalian TREX-2 complex that links transcription with nuclear messenger RNA export. Nucleic Acid Res. 40:4562-4573.
V.O.Wickramasinghe, R.Andrews, P.Ellis, C.Langford, J.B.Gurdon, M.Stewart, A.R.Venkitaraman, & R.A.Laskey. (2014). Selective mRNA export of specific classes of mRNA from mammalian nuclei is promoted by GANP. Nucleic Acids Res. 42:5059-5071 (doi:10.1093/nar/gku095).
D.Jani, E.Valkov & M.Stewart. (2014). Structural basis for the nuclear pore binding of the TREX-2 transcription-export complex and its function in mRNA nuclear export and re-positioning of active GAL1. Nucleic Acids Res. 42:6686-6697. doi:10.1093/nar/gku252.
L.Dimitrova, E.Valkov, S.Aibara, D.Flemming, S.H.McLaughlin, E.Hurt & M.Stewart. (2015). Structural characterization of the Chaetomium TREX-2 complex and its interaction with the mRNA nuclear export factor Mex67:Mtr2. Structure, 23:1246-1257 doi: 10.1016/j.str.2015.05.002.
E.Valkov & M.Stewart. (2015). 1.25 Å resolution structure of an RNA 20-mer that binds to the TREX2 complex. Acta Crystallogr. Ser. F. 71:1318-1321.
S.Aibara, W.Bai & M.Stewart. (2016). The Sac3 TPR-like region in the Saccharomyces cerevisiae TREX-2 complex is more extensive but independent of the CID region. J. Struct. Biol. 195:316-324 - doi: 10.1016/j.jsb.2016.07.007.
J.M.Gordon, S.Aibara & M.Stewart. (2017). Structure of the Sac3 RNA-Binding M-region in the Saccharomyces cerevisiae TREX-2 Complex. Nucl. Acids Res. 45:5577-5585. doi:10.1093/nar/gkx158.