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. 2019 Nov 15;8(11):561. doi: 10.3390/antiox8110561

Figure 3.

Figure 3

The role of PAK1 on UVB-induced MMP-1 expression in HaCaT cells. (A) A time course of UVB-induced phosphorylation of PAK1 in HaCaT cells. After serum-free starvation, cell were irradiated with UVB (30 mJ/cm2) at different time points as indicated, whole cell lysates were collected. (B) Effect of IPA-3 on UVB-induced MMP-1 expression in HaCaT cells. Cells pretreated with IPA-3 (5 and 10 μM) for 1 h were harvested 4 h after exposure to UVB (30 mJ/cm2). (C–E) Inhibitory effect of IPA-3 on UVB-induced phosphorylation of ERK, p38 and JNK signaling in HaCaT cells. Cells pretreated with IPA-3 (5 and 10 μM) for 1 h were harvested 15 min after exposure to UVB (30 mJ/cm2). Cells were treated with IPA-3 (5 and 10 μM) for 1 h before being exposed to UVB (30 mJ/cm2) and harvested 15 min later. (F) Effect of PGG on UVB-induced phosphorylation of PAK1. Cells were treated with PGG (10, 15 and 20 μM). After 1h, the cells were exposed to UVB (30 mJ/cm2) and harvested 15 min later. Western blot analysis was used to determine levels of MMP-1 expression and RAF, MEK, ERK, p90RSK, MKK4, JNK, MKK3/6, p38, and PAK1 phosphorylation using specific antibodies against the corresponding phosphorylated and total proteins. β-actin was used as loading control. Data are representative of three independent experiments that yielded similar results.