REF, an evolutionary conserved family of hnRNP-like proteins, interacts with TAP/Mex67p and participates in mRNA nuclear export.
Vertebrate TAP and its yeast ortholog Mex67p are involved in the export of messenger RNAs from the nucleus. TAP has also been implicated in the export of simian type D viral RNAs bearing the constitutive transport element (CTE). Although TAP directly interacts with CTE-bearing RNAs, the mode of interaction of TAP/Mex67p with cellular mRNAs is different from that with the CTE RNA and is likely to be mediated by protein-protein interactions. Here we show that Mex67p directly interacts with Yra1p, an essential yeast hnRNP-like protein. This interaction is evolutionarily conserved as Yra1p also interacts with TAP. Conditional expression in yeast cells implicates Yra1 p in the export of cellular mRNAs. Database searches revealed that Yra1p belongs to an evolutionarily conserved family of hnRNP-like proteins having more than one member in Mus musculus, Xenopus laevis, Caenorhabditis elegans, and Schizosaccharomyces pombe and at least one member in several species including plants. The murine members of the family directly interact with TAP. Because members of this protein family are characterized by the presence of one RNP-motif RNA-binding domain and exhibit RNA-binding activity, we called these proteins REF-bps for RNA and export factor binding proteins. Thus, Yra1p and members of the REF family of hnRNP-like proteins may facilitate the interaction of TAP/Mex67p with cellular mRNAs.
Stutz
F
F
Institute of Microbiology, Lausanne, Switzerland.
Bachi
A
A
Doerks
T
T
Braun
I C
IC
Séraphin
B
B
Wilm
M
M
Bork
P
P
Izaurralde
E
E
D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D002352:Carrier Proteins; D002467:Cell Nucleus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D017124:Conserved Sequence / Q000235:genetics*; D003593:Cytoplasm / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D018960:Hyaluronan Receptors; D008562:Membrane Glycoproteins; D051379:Mice; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D005810:Multigene Family; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029543:Nucleocytoplasmic Transport Proteins; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011951:Receptors, Complement / Q000737:chemistry / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012261:Ribonucleoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
C105242:ALYREF protein, human; C087299:C1QBP protein, human; C490193:C1qbp protein, mouse; D002352:Carrier Proteins; D005656:Fungal Proteins; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D018960:Hyaluronan Receptors; C106898:MEX67 protein, S cerevisiae; D008562:Membrane Glycoproteins; D024101:Mitochondrial Proteins; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011951:Receptors, Complement; D011993:Recombinant Fusion Proteins; C486334:Refbp1 protein, mouse; C486335:Refbp2 protein, mouse; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C105887:YRA1 protein, S cerevisiae; C032402:complement 1q receptor