Heparin was found to stimulate the phosphorylation of histone H1 but not protamine sulfate catalyzed by Ca2+/phospholipid-dependent protein kinase (protein kinase C or PKC). The effect of heparin on histone H1 phosphorylation appeared to be due to an increase in phosphatidylserine affinity for PKC activation in the presence of heparin. This effect of heparin was abolisched when trypsinized, cofactor-independent, PKC was employed to phosphorylate histone H1. These studies suggest that heparin acts at the regulatory domain of PKC, and emphasize the importance of the negative charge in influencing the accessibility of the substrate to PKC action.
|Original language||English (US)|
|Number of pages||4|
|State||Published - May 6 1991|
Bibliographical noteFunding Information:
Acknowledgements: We thank Mr Alan Davis for his assistance during the preparation of this naanuscript. These studies were supported in part by USPHS Research Grant CA-15062 awarded by the National Cancer Institute, DHHS, and by the Medical Researcla Fund of the US Department of Veterans Affairs.
- Protein kinase C
- Regulatory domain