Export and transport of tRNA are coupled to a multi-protein complex.
Vigilin is a ubiquitous multi heterogeneous nuclear ribonucleoprotein (hnRNP) K homologous (KH)-domain protein. Here we demonstrate that purified recombinant human vigilin binds tRNA molecules with high affinity, although with limited specificity. Nuclear microinjection experiments revealed for the first time that the immuno-affinity-purified nuclear vigilin core complex (VCC(N)) as well as recombinant vigilin accelerate tRNA export from the nucleus in human cells. The nuclear tRNA receptor exportin-t is part of the VCC(N). Elongation factor (EF)-1alpha is enriched in VCC(N) and its cytoplasmic counterpart VCC(C), whereas EF-1beta, EF-1gamma and EF-1delta are basically confined to the VCC(C). Our results suggest further that vigilin and exportin-t might interact during tRNA export, provide evidence that the channeled tRNA cycle is already initiated in the nucleus, and illustrate that intracellular tRNA trafficking is associated with discrete changes in the composition of cellular cytoplasmic multi-protein complexes containing tRNA.
Kruse
C
C
Department of Medical Molecular Biology, Medical University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany. kruse@molbio.mu-luebeck.de
Willkomm
D K
DK
Grünweller
A
A
Vollbrandt
T
T
Sommer
S
S
Busch
S
S
Pfeiffer
T
T
Brinkmann
J
J
Hartmann
R K
RK
Müller
P K
PK
D000818:Animals; D001692:Biological Transport; D015153:Blotting, Western; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism; D002467:Cell Nucleus / Q000737:chemistry / Q000378:metabolism; D002478:Cells, Cultured; D003593:Cytoplasm / Q000737:chemistry / Q000378:metabolism; D005347:Fibroblasts; D006801:Humans; D007700:Kinetics; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D008970:Molecular Weight; D029543:Nucleocytoplasmic Transport Proteins; D020648:Peptide Elongation Factor 1 / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D012343:RNA, Transfer / Q000008:administration & dosage / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000008:administration & dosage / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D013816:Thermodynamics; D014407:Tumor Cells, Cultured
D002352:Carrier Proteins; D029543:Nucleocytoplasmic Transport Proteins; D020648:Peptide Elongation Factor 1; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; C503618:XPOT protein, human; C075197:high density lipoprotein binding protein; D012343:RNA, Transfer