(A) Effect of FSS on pERK protein abundance in nuclear and cytosolic fractions of HUVEC. (B) Effect of ERK-binding mutant of Cx37 on FSS-induced HUVEC-FastFUCCI cell cycle. (C) In Cx37 KD background, the effect of HA-CX37FL and ERK-binding mutant of Cx37; HA-Cx37ΔCT on venous genes expression in FSS-induced HUVEC. (D) Polarized organization of HAEC cell towards the flow when expressed to arterial FSS. (E) Arterial FSS induces the late G1 arrest in HAEC cell and Notch inhibiton (DAPT), Cx37 KD, ERK inhibition, Foxo3a KD, and P27KD alter the cell cycle state of HAEC-FastFUCCI. (F) In Cx37 KD background, the effect of HA-Cx37FL and ERK-binding mutant of Cx37; HA-Cx37ΔCT on arterial and venous genes expression in FSS-induced HAEC. (A, B, C, E, F) Unpaired t test with Welch correction (A), two-way ANOVA (B, C, E, F) with Sidak’s multiple comparisons test. Scale bar: 100 μm (D). For all images, Data are means ± S.E.M; n = 3 independent experiments. ****P < 0.00001; ***P < 0.0001, **P < 0.001, *P < 0.01, n.s., not significant, P > 0.05.