Send to

Choose Destination
See comment in PubMed Commons below
J Chem Biol. 2009 Mar;2(1):27-37. doi: 10.1007/s12154-008-0013-3. Epub 2008 Oct 1.

Enhancement of the Ca(2+)-triggering steps of native membrane fusion via thiol-reactivity.

Author information

Department of Physiology and Biophysics, University of Calgary Faculty of Medicine, Calgary, AB, T2N 4N1, Canada.

Erratum in

  • J Chem Biol. 2011 Jan;4:31.


Ca(2+)-triggered membrane fusion is the defining step of exocytosis. Isolated urchin cortical vesicles (CV) provide a stage-specific preparation to study the mechanisms by which Ca(2+) triggers the merger of two apposed native membranes. Thiol-reactive reagents that alkylate free sulfhydryl groups on proteins have been consistently shown to inhibit triggered fusion. Here, we characterize a novel effect of the alkylating reagent iodoacetamide (IA). IA was found to enhance the kinetics and Ca(2+) sensitivity of both CV-plasma membrane and CV-CV fusion. If Sr(2+), a weak Ca(2+) mimetic, was used to trigger fusion, the potentiation was even greater than that observed for Ca(2+), suggesting that IA acts at the Ca(2+)-sensing step of triggered fusion. Comparison of IA to other reagents indicates that there are at least two distinct thiol sites involved in the underlying fusion mechanism: one that regulates the efficiency of fusion and one that interferes with fusion competency.

PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Springer Icon for PubMed Central
    Loading ...
    Support Center