Hormonal inhibition of endocytosis: novel roles for noradrenaline and G protein Gz

Y Zhao, Q Fang, SG Straub, M Lindau… - The Journal of …, 2010 - Wiley Online Library
Y Zhao, Q Fang, SG Straub, M Lindau, GWG Sharp
The Journal of Physiology, 2010Wiley Online Library
The modulation of endocytosis following exocytosis by noradrenaline (NA), a physiological
inhibitor of insulin secretion, was investigated in INS 832/13 cells using patch‐clamp
capacitance measurements. Endocytosis was inhibited by NA in a pertussis toxin‐
insensitive manner. Dialysing a synthetic peptide mimicking the C‐terminus of the α‐subunit
of Gz into the cells blocked the inhibition of endocytosis by NA. Cell‐attached capacitance
measurements indicated that inhibition by NA was due to a decreased number of …
The modulation of endocytosis following exocytosis by noradrenaline (NA), a physiological inhibitor of insulin secretion, was investigated in INS 832/13 cells using patch‐clamp capacitance measurements. Endocytosis was inhibited by NA in a pertussis toxin‐insensitive manner. Dialysing a synthetic peptide mimicking the C‐terminus of the α‐subunit of Gz into the cells blocked the inhibition of endocytosis by NA. Cell‐attached capacitance measurements indicated that inhibition by NA was due to a decreased number of endocytotic events without a change in vesicle size. Analysis of fission pore closure kinetics revealed two distinct fission modes, with NA selectively inhibiting the rapid fission pore closure events. Comparison of the actions of NA and deltamethrin, a calcineurin antagonist and potent inhibitor of endocytosis, demonstrated that they inhibit endocytosis by different mechanisms. These findings establish novel actions for NA and Gz in insulin‐secreting cells and possibly other cell types.
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