Journal article
Transgenic incorporation of skeletal TnT into cardiac myofilaments blunts PKC-mediated depression of force
American journal of physiology. Heart and circulatory physiology, Vol.280(3), pp.H1011-1018
03/2001
Handle:
https://hdl.handle.net/2376/114093
PMID: 11179042
Abstract
Protein kinase C (PKC)-mediated phosphorylation of cardiac troponin I (cTnI) and troponin T (cTnT) has been shown to diminish maximum activation of myofilaments. The functional role of cTnI phosphorylation has been investigated. However, the impact of cTnT phosphorylation on myofilament force is not well studied. We tested the effect of endogenous PKC activation on steady-state tension development and Ca(2+) sensitivity in skinned fiber bundles from transgenic (TG) mouse hearts expressing fast skeletal TnT (fsTnT), which naturally lacks the PKC sites present in cTnT. The 12-O-tetradecanoylphorbol 13-acetate (TPA) treatment induced a 29% (46.1 +/- 2.5 vs. 33.4 +/- 2.6 mN/mm(2)) reduction in maximum tension in the nontransgenic (NTG) preparations (n = 7) and was inhibited with chelerythrine. However, TPA did not induce a change in the maximum tension in the TG preparations (n = 11). TPA induced a small but significant (P < 0.02) increase in Ca(2+) sensitivity (untreated pCa(50) = 5.63 +/- 0.01 vs. treated pCa(50) = 5.72 +/- 0.01) only in TG preparations. In TG preparations, (32)P incorporation was not evident in TnT and was also significantly diminished in cTnI, compared with NTG. Our data indicate that incorporation of fsTnT into the cardiac myofilament lattice blunts PKC-mediated depression of maximum tension. These data also suggest that cTnT may play an important role in amplifying the myofilament depression induced by PKC-mediated phosphorylation of cTnI.
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Details
- Title
- Transgenic incorporation of skeletal TnT into cardiac myofilaments blunts PKC-mediated depression of force
- Creators
- D E Montgomery - Program in Cardiovascular Sciences, Department of Physiology and Biophysics, College of Medicine, University of Illinois, Chicago, Illinois 60612, USAM ChandraQ HuangJ JinR J Solaro
- Publication Details
- American journal of physiology. Heart and circulatory physiology, Vol.280(3), pp.H1011-1018
- Academic Unit
- Integrative Physiology and Neuroscience, Department of
- Publisher
- United States
- Grant note
- R37-HL-22231 / NHLBI NIH HHS
- Identifiers
- 99900548255301842
- Language
- English
- Resource Type
- Journal article