Palmitate antagonises the stimulus-induced activation of ERK and CaMKII in MIN6 β cells.

MIN6 β cells were incubated with 10 µM KN62 (an inhibitor of CaMKII) for 2 h. In the last hour of this incubation cells were incubated with either glucose (16 mM) or amino acids (10 mM) prior to assessing (A) GSIS or AASIS, (B) ERK activation by analysis of ERK^{Thr202/Tyr204} phosphorylation. Total ERK content was used for assaying protein loading. Alternatively, MIN6 β cells were incubated in the absence or presence of palmitate (0.4 mM) for 48 h and then stimulated insulin secretion assessed by the addition of glucose or amino acids for 1 h at the concentrations indicated. Cells were lysed and lysates immunoblotted to assay phospho-CaMKII^Thr286 phosphorylation with native CaMKII serving as a gel loading control (C). Bars represent mean ± SEM from 3 separate experiments and asterisks signify a significant difference from the untreated control values (P<0.05).