Báo cáo khoa học: Tyrosine phosphorylation of calponins Inhibition of the interaction with F-actin

Tyrosine Phosphorylation of Calponins: Inhibition of the Interaction with F-actin

Authors: Julien Abouzaglou, Christine Bénistant, Mario Gimona, Claude Roustan, Rhida Kassab, and Abdellatif Fattoum

Field: Biochemistry

Document Summary:

This research investigates the tyrosine phosphorylation of calponin isoforms, specifically calponin h1 and h3, by the Fyn tyrosine kinase. The study demonstrates that tyrosine phosphorylation of calponins leads to a significant decrease in their binding affinity to F-actin. This phenomenon was observed both in vitro and in cultured COS 7 cells. The research identifies specific tyrosine residues (Tyr261 in calponin h3 and Tyr261 and Tyr182 in calponin h1) as sites of phosphorylation. The findings suggest that tyrosine phosphorylation represents a novel mechanism for regulating the interaction between calponins and F-actin, potentially influencing cellular processes involving the actin cytoskeleton.

Detailed Table of Contents:

• Materials and Methods
• Chemicals
• Protein preparations
• Tyrosine phosphorylation of calponins with Fyn
• Cell culture and transfections
• Electrophoresis and immunoblots
• Co-sedimentation assays
• Structural analyses of tryptic phosphopeptides
• Results
• Tyrosine phosphorylation of calponin h3 in COS 7 cells
• In vitro phosphorylation of calponin h3 and calponin h1 by Fyn tyrosine kinase
• Inhibition of actin binding to tyrosine-phosphorylated calponins
• Identification of the tyrosine phosphorylation sites of calponin h3 and calponin h1
• Discussion
• Acknowledgements
• References