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. 2021 Mar 5;320(5):H1822–H1835. doi: 10.1152/ajpheart.00673.2020

Table 3.

Results for rates of force release, kf,rel, at maximal calcium activation pCa 4.8 and submaximal pCa 5.75

kf,rel (s−1) at pCa 4.8 NTGβ NTGβ,PKA t/tβ t/tβ,PKA ANOVA
n 9 8 10 10
Pi (mM) = 0 46.96 ± 1.16 56.86 ± 2.74 63.31 ± 2.40 61.70 ± 1.26 Main effects
1 49.01 ± 2.06 62.68 ± 2.76 67.39 ± 2.19 70.74 ± 2.47 †MYBPC3, †Pi, †PKA
2 50.39 ± 2.15 64.55 ± 3.70 71.23 ± 2.38 77.41 ± 2.78
3 51.50 ± 2.24 69.78 ± 3.73 78.09 ± 2.05 82.30 ± 2.26 Interactions
4 55.78 ± 2.40 74.02 ± 4.40 80.59 ± 2.31 87.29 ± 2.99 †Pi × MYBPC3
5 60.05 ± 2.12 76.68 ± 3.90 85.63 ± 2.52 92.70 ± 2.64 †Pi × PKA
8 61.17 ± 2.72 80.35 ± 3.29 93.04 ± 2.41 99.86 ± 3.19
12 63.60 ± 3.35 86.86 ± 3.25 96.71 ± 3.25 106.46 ± 3.54
Δkf,rel/ΔPi 2.15 ± 0.24 3.27 ± 0.48 4.35 ± 0.37 5.51 ± 0.30 †MYBPC3, †PKA
kf,rel (s-1) at pCa 5.75
Pi (mM) = 0 50.59 ± 1.87 64.13 ± 3.88 73.30 ± 3.31 70.59 ± 2.45 Main effects
1 52.22 ± 1.84 65.87 ± 2.21 76.84 ± 3.33 72.80 ± 2.45 †MYBPC3, †Pi, †PKA
2 54.76 ± 2.41 66.53 ± 2.20 80.43 ± 3.67 79.32 ± 2.93
3 57.71 ± 2.26 68.76 ± 2.31 83.87 ± 2.73 82.54 ± 2.60 Interactions
4 60.26 ± 2.18 75.74 ± 2.12 88.13 ± 3.46 84.86 ± 2.46 †PKA × MYBPC3
5 63.81 ± 2.19 79.94 ± 2.70 89.95 ± 3.24 89.34 ± 2.60
8 66.37 ± 2.35 85.50 ± 2.96 93.21 ± 3.45 95.84 ± 3.19
12 69.76 ± 2.42 83.84 ± 3.60 93.66 ± 3.74 94.29 ± 2.19
Δkf,rel/ΔPi 2.64 ± 0.25 2.68 ± 0.54 3.45 ± 0.33 3.81 ± 0.37 *MYBPC3

Values are means ± SE; n, number of strips. The sensitivity of kf,rel to Pi, Δkf,rel/ΔPi, was calculated as the slope of linear regression using values measured at 0–5 mM Pi. Statistical results reflect repeated-measures ANOVA. Two-way ANOVA was then used to determine whether Δkf,rel/ΔPi was influenced by absence of cMyBP-C and/or PKA. *P < 0.05, †P < 0.01. NTGβ, nontransgenic; t/tβ, transgenic lacking cMyBP-C; PKA, protein kinase A.