Figure 4. The time-of-day variations in agonist-induced MLC₂₀ phosphorylation are diminished in mesenteric arteries from SM-Bmal1–KO mice.

(A and C) Representative urea/glycerol gel (A) and quantitative data (C; n = 7) of MLC₂₀ phosphorylation induced by PE (100 μM) plus 5-HT (10 μM) for 2 minutes. Un-P MLC₂₀, unphosphorylated MLC₂₀; Mono-P MLC₂₀, monophosphorylated MLC₂₀; Di-P MLC₂₀, diphosphorylated MLC₂₀; MLC₂₀-T, total MLC₂₀, including un-, mono-, and diphosphorylated MLC₂₀. (B and D) Representative Western blots (B) and quantitative data (D; n = 8) of MLC₂₀ phosphorylation induced by PE plus 5-HT using the antibodies specific for phosphorylated MLC₂₀ (Thr18 and Ser19) and total MLC₂₀ protein.