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Updated: Feb 20, 2026

Analysis of Cardiac Contractile Dysfunction and Ca2+ Transients in Rodent Myocytes
Published on: May 25, 2022
Secondary phosphorylation in myocytes expressing FLAG-tagged and non-tagged phospho-mimetic cardiac troponin I
Sarah E Lang1,2, Tamara K Stevenson1, Tabea M Schatz1
1Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA.
Abstract:
Secondary phosphorylation develops in myocytes expressing phospho-mimetic cardiac troponin I (cTnI) but it is not known whether multiple substitutions (e.g. cTnISDTD and cTnIS4D) cause preferential phosphorylation of the remaining endogenous or the phospho-mimetic cTnI in intact myocytes. Western analysis was performed to determine whether the FLAG/total cTnI ratios are similar for phosphorylated versus total cTnI in myocytes expressing phospho-mimetic cTnI with Asp(D) substitutions at S43/45 plus S23/24 (cTnIS4D) or T144 (cTnISDTD). Representative Western analysis of phosphorylated S23/24 (p-S23/24) and S150 (p-S150) are presented along with re-probes using an antibody which detects all cTnI (MAB1691 Ab). The level of p-S150 also is compared to results obtained using single S43D and/or S45D phospho-mimetic substitutions. These results are discussed in more detail in Lang et al. [1].
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