Human DNA helicase IV is nucleolin, an RNA helicase modulated by phosphorylation.
The cDNA encoding human DNA helicase IV (HDH IV), a 100-kDa protein which unwinds DNA in the 5' to 3' direction with respect to the bound strand, was cloned and sequenced. It was found to be identical to the human cDNA encoding nucleolin, a ubiquitous eukaryotic protein essential for pre-ribosome assembly. HDH IV/nucleolin can unwind RNA-RNA duplexes, as well as DNA-DNA and DNA-RNA duplexes. Phosphorylation of HDH IV/nucleolin by cdc2 kinase and casein kinase II enhanced its unwinding activity in an additive way. The Gly-rich C-terminal domain possesses a limited ATP-dependent duplex-unwinding activity which contributes to the helicase activity of HDH IV/nucleolin.
Tuteja
N
N
International Centre for Genetic Engineering and Biotechnology, Area Science Park, Trieste, Italy.
Huang
N W
NW
Skopac
D
D
Tuteja
R
R
Hrvatic
S
S
Zhang
J
J
Pongor
S
S
Joseph
G
G
Faucher
C
C
Amalric
F
F
D000251:Adenosine Triphosphatases / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D015153:Blotting, Western; D016203:CDC2 Protein Kinase / Q000378:metabolism; D047390:Casein Kinase II; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism; D004265:DNA Helicases / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D006367:HeLa Cells / Q000201:enzymology; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D016601:RNA-Binding Proteins; D017385:Sequence Homology; D000097796:Nucleolin
D000251:Adenosine Triphosphatases; D000255:Adenosine Triphosphate; D016203:CDC2 Protein Kinase; D047390:Casein Kinase II; D004247:DNA; D004265:DNA Helicases; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D017346:Protein Serine-Threonine Kinases; D016601:RNA-Binding Proteins; D000097796:Nucleolin; C059716:helD protein, E coli