Glucose stimulation of protein acylation in the pancreatic β-cell

Abstract

Aims To determine whether protein acylation plays a role in the effects of glucose on the insulin secreting β-cell. Main methods The measurement of 3H-palmitate incorporation into protein in the INS 832/13 cell that has a robust and well-characterized biphasic insulin secretory response to stimulation with glucose. Key findings Stimulating the cells with glucose increased the incorporation of 3H-palmitic acid into protein by up to 90%. Similarly, 2-aminobicyclo [2.2.1] heptane-2-carboxylic acid (BCH) the non-metabolizable analog of leucine that mimics the stimulatory effect of glucose on insulin secretion also increased the incorporation of 3H-palmitic acid into protein. Treatment of cell lysates with hydroxylamine substantially reduced the incorporation indicating that most of the incorporation was due to enzymatic palmitoylation of proteins. Cerulenin, a classical inhibitor of protein acylation also substantially reduced the incorporation. Using PAGE and autoradiography a glucose-induced increase in protein palmitoylation and specific glucose-induced increases in the palmitoylation of proteins of 30, 44, 48 and 76 kD were identified. Significance The data suggest that protein acylation plays multiple roles in β-cell function.