TAP/NXF1, the primary mRNA export receptor, specifically interacts with a neuronal RNA-binding protein HuD.
Hu proteins are RNA-binding proteins that are implicated in the control of stabilization, nuclear export, and/or translation of specific mRNAs with AU-rich elements (AREs) in the 3'-untranslated region. Three neuron-specific Hu proteins (HuD, HuB, and HuC), but not a ubiquitously expressed Hu protein HuR, have an activity to induce neurite outgrowth when they are overexpressed in a rat neuronal cell line PC12. Here we show that TAP/NXF1, the primary export receptor for the bulk mRNA, is a specific binding partner for HuD. In vitro binding experiments using recombinant proteins revealed that the interaction between TAP and HuD is direct and that HuD can form a ternary complex together with both TAP and RNA. Interestingly, HuR does not interact with TAP. These results suggest that HuD acts as a novel adaptor protein to recruit TAP for efficient export of ARE-containing mRNAs in neuronal cells.
Saito
Kuniaki
K
Department of Biology, Graduate School of Science and Technology, Kobe University, 1-1 Rokkodaicho, Nadaku, Kobe 657-8501, Japan.
Fujiwara
Toshinobu
T
Katahira
Jun
J
Inoue
Kunio
K
Sakamoto
Hiroshi
H
D000818:Animals; D001665:Binding Sites; D051959:ELAV Proteins; D000067779:ELAV-Like Protein 4; D006367:HeLa Cells; D006801:Humans; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016501:Neurites / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D029543:Nucleocytoplasmic Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016716:PC12 Cells; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D034443:RNA Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017384:Sequence Deletion / Q000235:genetics
D051959:ELAV Proteins; D000067779:ELAV-Like Protein 4; C498010:ELAVL4 protein, human; C122111:NXF1 protein, human; D009419:Nerve Tissue Proteins; D029543:Nucleocytoplasmic Transport Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins