Ratcheting mRNA out of the nucleus.
Export of mature mRNA to the cytoplasm is the culmination of the nuclear portion of eukaryotic gene expression. After transport-competent mature mRNP export complexes are formed in the nucleus, their passage through nuclear pore complexes (NPCs) is facilitated by the Mex67:Mtr2 heterodimer. At the NPC cytoplasmic face, mRNP remodeling prevents its return to the nucleus and so functions as a molecular ratchet imposing directionality on transport. In budding yeast, recent work suggests that the DEAD-box helicase Dbp5 remodels mRNPs at the NPC cytoplasmic face by removing Mex67 and that the Dbp5 ATPase is activated by Gle1 and inositol hexaphosphate (IP(6)).
Stewart
Murray
M
MRC Laboratory of Molecular Biology, Hills Road, Cambridge, UK. ms@mrc-lmb.cam.ac.uk
D021581:Active Transport, Cell Nucleus / Q000502:physiology; D002352:Carrier Proteins / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism*; D053487:DEAD-box RNA Helicases / Q000502:physiology; D019281:Dimerization; D026901:Membrane Transport Proteins / Q000378:metabolism; D008954:Models, Biological; D028861:Nuclear Pore Complex Proteins / Q000502:physiology; D009687:Nuclear Proteins / Q000378:metabolism; D029543:Nucleocytoplasmic Transport Proteins / Q000378:metabolism / Q000502:physiology; D010833:Phytic Acid / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D020365:RNA Helicases / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D012261:Ribonucleoproteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism / Q000502:physiology
D002352:Carrier Proteins; C101408:GLE1 protein, S cerevisiae; C106898:MEX67 protein, S cerevisiae; D026901:Membrane Transport Proteins; C480169:Mtr2 protein, S cerevisiae; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; C026452:messenger ribonucleoprotein; D010833:Phytic Acid; C492382:DBP5 protein, S cerevisiae; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases