Activation of casein kinase II in ML-1 human myeloblastic leukemia cells requires IGF-1 and transferrin.
Casein kinase II (CK II), a key enzyme involved in the regulation of cell growth, has been variously reported to be activated by diverse mitogens, including insulin-like growth factor 1 (IGF-1) and epidermal growth factor (EGF). Activation of the enzyme is generally carried out in the presence of serum, and we examined the question whether serum components participate in the activation process. We demonstrated previously that ML-1 cells require IGF-1 plus transferrin (TF) for growth and transforming growth factor beta or tumor necrosis factor alpha plus TF for differentiation. We now found that CK II is activated only when the cells are exposed to both IGF-1 and TF or when TF is replaced in this combination with relatively high levels of iron salts. Induction of differentiation with TGF-beta and TF did not result in CK II activation. These results show that CK II activation in ML-1 cells requires the application of both components of the growth signal, IGF-1 and TF, demonstrating that the growth factor alone is incapable of enhancing the activity of the enzyme.
Roswell Park Cancer Institute, Grace Cancer Drug Center, Buffalo, NY 14213.
L G
LG
Wang
X M
XM
Liu
H
H
Wikiel
A
A
Bloch
D000595:Amino Acid Sequence; D047390:Casein Kinase II; D002455:Cell Division / Q000187:drug effects; D016895:Culture Media, Serum-Free; D003513:Cycloheximide / Q000494:pharmacology; D004789:Enzyme Activation; D005296:Ferrous Compounds / Q000494:pharmacology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D015470:Leukemia, Myeloid, Acute / Q000201:enzymology* / Q000473:pathology; D008969:Molecular Sequence Data; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D014168:Transferrin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D016895:Culture Media, Serum-Free; D005296:Ferrous Compounds; D014168:Transferrin; C020748:ferrous sulfate; D007334:Insulin-Like Growth Factor I; D003513:Cycloheximide; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases