PML is required for homeodomain-interacting protein kinase 2 (HIPK2)-mediated p53 phosphorylation and cell cycle arrest but is dispensable for the formation of HIPK domains.
Here we demonstrate that endogenous human homeodomain-interacting protein kinase (HIPK) 2 and the highly homologous kinase HIPK3 are found in a novel subnuclear domain, the HIPK domains. These are distinct from other subnuclear structures such as Cajal bodies and nucleoli and show only a partial colocalization with promyelocytic leukemia (PML) nuclear bodies (PML-NBs). A kinase inactive HIPK2 point mutant is localized in the nucleoplasm. The occurrence of HIPK domains in PML-/- fibroblasts reveals their independence from the PML protein. HIPK2 can be almost completely recruited to PML-NBs by the PML isoform PML IV, but not by PML-III. PML IV-mediated recruitment of HIPK2 does not rely on its kinase function and also occurs in PML-/- fibroblasts, showing that this PML isoform is sufficient for recruitment of HIPK2. Whereas the architecture of HIPK domains is PML independent, HIPK2-mediated enhancement of p53-dependent transcription, p53 serine 46 phosphorylation and the antiproliferative function of HIPK2 strictly rely on the presence of PML.
Möller
Andreas
A
Division of Immunochemistry, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany.
Sirma
Hüseyin
H
Hofmann
Thomas G
TG
Rueffer
Sven
S
Klimczak
Elisabeth
E
Dröge
Wulf
W
Will
Hans
H
Schmitz
M Lienhard
ML
D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis; D006801:Humans; D009363:Neoplasm Proteins / Q000378:metabolism*; D009687:Nuclear Proteins; D012516:Osteosarcoma / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D000071156:Promyelocytic Leukemia Protein; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D013347:Subcellular Fractions / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000378:metabolism*; D025521:Tumor Suppressor Proteins
C493956:CDKN1A protein, human; D002352:Carrier Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D000071156:Promyelocytic Leukemia Protein; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C070576:PML protein, human; C115114:HIPK2 protein, human; D017346:Protein Serine-Threonine Kinases