Association of CPI-17 with protein kinase C and casein kinase I.
The protein kinase C-potentiated inhibitor protein of 17kDa, called CPI-17, specifically inhibits myosin light chain phosphatase (MLCP). Phosphorylation of Thr-38 in vivo highly potentiates the ability of CPI-17 to inhibit MLCP. Thr-38 has been shown to be phosphorylated in vitro by a number of protein kinases including protein kinase C ... (PKC), Rho-associated coiled-coil kinase (ROCK), and protein kinase N (PKN). In this study we have focused on the association of protein kinases with CPI-17. Using affinity chromatography and Western blot analysis, we found interaction with all PKC isotypes and casein kinase I isoforms, CKIalpha and CKI. By contrast, ROCK and PKN did not associate with CPI-17, suggesting that PKC may be the relevant kinase that phosphorylates Thr-38 in vivo. CPI-17 interacted with the cysteine-rich domain of PKC and was phosphorylated by all PKC isotypes. We previously found that CPI-17 co-purified with casein kinase I in brain suggesting they are part of a complex and we now show that CPI-17 associates with the kinase domain of CKI isoforms.
Mesh Terms:
Animals, Binding Sites, Brain, Casein Kinases, Catalytic Domain, Humans, Isoenzymes, Muscle Proteins, Phosphoprotein Phosphatases, Phosphoproteins, Phosphorylation, Protein Kinase C, Protein Kinases, Protein Structure, Tertiary
Animals, Binding Sites, Brain, Casein Kinases, Catalytic Domain, Humans, Isoenzymes, Muscle Proteins, Phosphoprotein Phosphatases, Phosphoproteins, Phosphorylation, Protein Kinase C, Protein Kinases, Protein Structure, Tertiary
Biochem. Biophys. Res. Commun.
Date: Mar. 26, 2004
PubMed ID: 15003508
View in: Pubmed Google Scholar
Download Curated Data For This Publication
149813
Switch View:
- Interactions 19