Bisphosphorylation of cardiac troponin I modulates the Ca2+‐dependent binding of myosin subfragment S1 to reconstituted thin filaments
- 8 April 1996
- journal article
- Published by Wiley in FEBS Letters
- Vol. 384 (1) , 43-47
- https://doi.org/10.1016/0014-5793(96)00274-8
Abstract
We have reconstituted thin filaments comprising pyrene-labelled actin (pyr-actin), tropomyosin (Tm) and cardiac troponin (cTn). cTn was isolated in two defined phosphorylation states; completely dephosphorylated on all subunits and with only the cTnI subunit bisphosphorylated. The thin filament was saturated with cTn at a pyr-actin/Tm/cTn ratio of 7:1:1. The calcium-dependent binding of S1 to thin filaments was measured in a stopped-flow spectrophotometer and the dependence of the observed rate constant on [Ca2+] fitted to the Hill equation. The only significant difference between the two phosphorylation states of the filaments was a 0.36 decrease in the pCa50 on bisphosphorylation.Keywords
This publication has 28 references indexed in Scilit:
- The Unique Amino-terminal Peptide of Cardiac Troponin I Regulates Myofibrillar Activity Only When it is PhosphorylatedJournal of Molecular and Cellular Cardiology, 1995
- Pattern Formation on Cardiac Troponin I by Consecutive Phosphorylation and DephosphorylationEuropean Journal of Biochemistry, 1995
- A site phosphorylated in bovine cardiac troponin T by cardiac CaM kinase IIBiochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, 1995
- Characterization of the Equilibrium Between Blocked and Closed States of Muscle Thin FilamentsEuropean Journal of Biochemistry, 1995
- Troponin replacement in permeabilized cardiac muscle Reversible extraction of troponin I by incubation with vanadateFEBS Letters, 1992
- Ordered phosphorylation of a duplicated minimal recognition motif for cAMP‐dependent protein kinase present in cardiac troponin IFEBS Letters, 1992
- Effect of removal and reconstitution of troponins C and I on the Ca2+‐activated tension development of single glycerinated rabbit skeletal muscle fibersEuropean Journal of Biochemistry, 1992
- Structure-function relationships in cardiac troponin TBiochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, 1989
- The Protein Phosphatases Involved in Cellular Regulation. 1. Classification and Substrate SpecificitiesEuropean Journal of Biochemistry, 1983
- Intrinsic fluorescence of actinBiochemistry, 1972