The regulatory domain of protein kinase C beta 1 contains phosphatidylserine- and phorbol ester-dependent calcium binding activity.
Certain isoforms of protein kinase C (PKC) require both Ca2+ and phospholipid for optimum activity. However, little is known about the nature of the interaction between PKC and Ca2+. The present study demonstrates that the isolated regulatory domain of PKC beta 1, when synthesized as a fusion protein in Escherichia coli, binds 45Ca2+ with high affinity, but only in the presence of phosphatidylserine or 12-O-tetradecanoyl-phorbol-13-acetate. This binding is highly selective for Ca2+ since it is preferentially inhibited by excess non-radioactive Ca2+ when compared with the cations Mg2+, Mn2+, Na+, or K+. It appears, therefore, that the binding of Ca2+ to PKC requires a complex tertiary structure in the regulatory domain.
Luo
J H
JH
Comprehensive Cancer Center, Columbia University, New York, New York 10032.
Kahn
S
S
O'Driscoll
K
K
Weinstein
I B
IB
D001483:Base Sequence; D001665:Binding Sites; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005822:Genetic Vectors; D005982:Glutathione Transferase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D010718:Phosphatidylserines / Q000494:pharmacology*; D010957:Plasmids; D011493:Protein Kinase C / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism; D015183:Restriction Mapping; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D007527:Isoenzymes; D009838:Oligodeoxyribonucleotides; D010718:Phosphatidylserines; D011993:Recombinant Fusion Proteins; D005982:Glutathione Transferase; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium