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.
This research output has an Altmetric Attention Score of 3. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 24 December 2022.
All research outputs
#12,345,312
of 34,365,356 outputs
Outputs from American Journal of Physiology: Heart & Circulatory Physiology
#2,820
of 7,398 outputs
Outputs of similar age
#26,665
of 61,674 outputs
Outputs of similar age from American Journal of Physiology: Heart & Circulatory Physiology
#12
of 49 outputs
Altmetric has tracked 34,365,356 research outputs across all sources so far. This one is in the 38th percentile – i.e., 38% of other outputs scored the same or lower than it.
So far Altmetric has tracked 7,398 research outputs from this source. They typically receive a little more attention than average, with a mean Attention Score of 6.2. This one is in the 28th percentile – i.e., 28% of its peers scored the same or lower than it.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 61,674 tracked outputs that were published within six weeks on either side of this one in any source. This one is in the 8th percentile – i.e., 8% of its contemporaries scored the same or lower than it.
We're also able to compare this research output to 49 others from the same source and published within six weeks on either side of this one. This one is in the 6th percentile – i.e., 6% of its contemporaries scored the same or lower than it.
