Architecture of high mobility group protein I-C.DNA complex and its perturbation upon phosphorylation by Cdc2 kinase.
The high mobility group I-C (HMGI-C) protein is an abundant component of rapidly proliferating undifferentiated cells. High level expression of this protein is characteristic for early embryonic tissue and diverse tumors. HMGI-C can function as an architectural factor enhancing the activity of transcription factor NF-kappaB on the beta-interferon promoter. The protein has three minor groove DNA-binding domains (AT-hooks). Here, we describe the complex of HMGI-C with a fragment of the beta-interferon promoter. We show that the protein binds to NRDI and PRDII elements of the promoter with its first and second AT-hook, respectively. Phosphorylation by Cdc2 kinase leads to a partial derailing of the AT-hooks from the minor groove, affecting mainly the second binding domain. In contrast, binding to long AT stretches of DNA involves contacts with all three AT-hooks and is marginally sensitive to phosphorylation. Our data stress the importance of conformation of the DNA binding site and protein phosphorylation for its function.
Schwanbeck
R
R
III Zoologisches Institut, Entwicklungsbiologie, Universität Göttingen, Humboldtallee 34A, D-37073 Göttingen, Germany.
Manfioletti
G
G
Wiśniewski
J R
JR
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016203:CDC2 Protein Kinase / Q000737:chemistry / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D018983:DNA Footprinting; D004305:Dose-Response Relationship, Drug; D025743:HMGA2 Protein; D006609:High Mobility Group Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016899:Interferon-beta / Q000235:genetics / Q000378:metabolism; D008745:Methylation; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011487:Protein Conformation
D025743:HMGA2 Protein; D006609:High Mobility Group Proteins; D016899:Interferon-beta; D004247:DNA; D016203:CDC2 Protein Kinase