Skip to main content
Log in

Protein kinase C inhibition by calmodulin and its fragments

  • Published:
Journal of Protein Chemistry Aims and scope Submit manuscript

Abstract

Inhibition of protein kinase C (PKC) by calmodulin is investigated and we describe the localization of inhibitory sequences within the calmodulin molecule. We present evidence that calmodulin inhibits PKC through an inhibition of the activation of PKC associated with lipid membranes: Binding of PKC to lipid vesicles is not affected, but activation is abolished. The potent calmodulin antagonist R24571 (calmidazol) did not affect the inhibition of PKC by calmodulin at concentrations up to 10−5 M. Two tryptic fragments of calmodulin were isolated which inhibited PKC. They were only slightly less potent than intact calmodulin with an IC50 of 6 µ M compared to 1 µ M of intact calmodulin. They were identified as Ser38-Arg74 and His107-Lys148. Each of the inhibiting fragments contains an intact Ca2+-binding domain with complete helix-loop-helix structure (“EF hand”). Other calmodulin peptides showed only weak inhibitory activity. Both fragments did not stimulate cAMP phosphodiesterase even at concentrations 100-fold higher than the calmodulin concentration needed for maximal stimulation. None of the fragments acted as a calmodulin antagonist.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Krüger, H., Schröder, W., Buchner, K. et al. Protein kinase C inhibition by calmodulin and its fragments. J Protein Chem 9, 467–473 (1990). https://doi.org/10.1007/BF01024623

Download citation

  • Received:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF01024623

Key words

Navigation