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. 2010 Nov 17;25(1):138–156. doi: 10.1210/me.2010-0217

Figure 3.

Figure 3

ERK activation in HBL cells is independent of cAMP. A, Inability of FSK to induce ERK phosphorylation. Serum-starved HBL cells were incubated with FSK (10−5 m) for the times indicated or with the positive controls NDP-MSH (10−7 m, 5 min) or PMA (0.1 ng/μl, 15 min). Cell lysates were analyzed for pERK or ERK2 as loading control. B, The adenylyl cyclase inhibitor DDA does not block MC1R-induced ERK activation. HBL cells were challenged with NDP-MSH (10−7 m, 5 or 30 min) or FSK (10–5 m, 30 min), with or without DDA (2.5 mm, 30 min). ERK phosphorylation was detected by Western blot. C, HBL cells were treated as above and intracellular cAMP levels were determined. Results are given as mean ± sem (n ≥ 4).