A novel shuttle protein binds to RNA helicase A and activates the retroviral constitutive transport element.
The constitutive transport element (CTE) of type D retroviruses mediates the nuclear export of unspliced viral transcripts. We previously showed that RNA helicase A functionally interacts with CTE and contains a bidirectional nuclear transport domain at the carboxyl terminus. Here we report the identification of a novel human protein, helicase A-binding protein 95 (HAP95), which specifically binds to the carboxyl terminus of RNA helicase A. HAP95 is partially homologous to AKAP95, a member of the A kinase-anchoring protein family, but lacks the protein kinase A binding domain characteristic of this family. HAP95 is a nuclear protein at steady state but shuttles between the nucleus and cytoplasm. Overexpression of HAP95 significantly increases CTE-dependent gene expression but has no effect on general gene expression or that mediated by the Rev/Rev response element of human immunodeficiency virus type 1.
Westberg
C
C
Departments of Biology and Medicine, University of California, San Diego, La Jolla, California 92093-0665, USA.
Yang
J P
JP
Tang
H
H
Reddy
T R
TR
Wong-Staal
F
F
D000595:Amino Acid Sequence; D001324:Autoantigens / Q000378:metabolism*; D001483:Base Sequence; D030121:Betaretrovirus / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D053487:DEAD-box RNA Helicases; D004268:DNA-Binding Proteins; D005260:Female; D015723:Gene Library; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D020365:RNA Helicases / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013601:T-Lymphocytes / Q000378:metabolism; D014162:Transfection
C490117:AKAP8L protein, human; D001324:Autoantigens; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011994:Recombinant Proteins; C098487:DHX9 protein, human; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases