Nature of the intrinsic protein kinases involved in phosphorylation of non-histone proteins in intact prostatic nuclei: further identification of androgen-sensitive protein kinase reactions |
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Authors: | Said A Goueli Khalil Ahmed |
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Institution: | (1) Cellular and Molecular Biochemistry Laboratory, Research Service (151) and Department of Laboratory Medicine and Pathology, University of Minnesota, USA;(2) U. S. Department of Veterans Affairs Medical Center, One Veterans Drive, 55417 Minneapolis, MN, USA |
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Abstract: | Nuclei isolated from rat ventral prostate contain a number of messenger-dependent and -independent protein kinases. Studies were undertaken to determine the relative contribution of these protein kinases in phosphorylation of non-histone proteins (NHPs) in isolated nuclei. The data suggest that messenger-dependent protein kinases such as those dependent on cAMP or Ca2+/calmodulin or Ca2–/phospholipid may be present in very small amounts in intact isolated nuclei, and thus appear not to be significantly involved in phosphorylation of endogenous NHPs. Messenger-independent nuclear associated protein kinases PK-N1 and PK-N2 are known to catalyze the phosphorylation of NHPs in vitro (Goueli SA, et al., Eur J Biochem 113: 45–51, 1980). Of these, the intrinsic heparin-sensitive PK-N2 as compared with heparin-insensitive PK-N1 appeared to be the predominant protein kinase engaged in phosphorylation of NHPs in intact nuclei. About 78–88% of NHP phosphorylation in intact nuclei was inhibited by heparin suggesting that the remaining 12–22% phosphorylation of NHPs was catalyzed via the heparin-insensitive protein kinase(s). Further, the data provide additional evidence that heparin-sensitive PK-N2 is the one that is most responsive to androgenic status in the animal.Abbreviations NHP
Non-Histone Protein
- PMSF
Phenylmethylsulfonyl Fluoride
- DTT
Dithiothreitol
- SDS
Sodium Dodecyl Sulfate |
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Keywords: | nuclear messenger-independent protein kinases non-histone protein phosphorylation nuclear casein kinases messenger-dependent protein kinases prostate androgen action |
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