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Rhythmic opening and closing of vesicles during constitutive exo‐ and endocytosis in chromaffin cells
Author(s) -
Henkel A.W.,
Meiri H.,
Horstmann H.,
Lindau M.,
Almers W.
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.1.84
Subject(s) - endocytosis , staurosporine , endocytic cycle , biology , vesicle , microbiology and biotechnology , biophysics , bulk endocytosis , exocytosis , cell , biochemistry , protein kinase c , membrane , kinase
Constitutive exo‐ and endocytic events are expected to increase and diminish the cell surface area in small spontaneous steps. Indeed, cell‐attached patch–clamp measurements in resting chromaffin cells revealed spontaneous upward and downward steps in the electrical capacitance of the plasma membrane. The most frequent step size indicated cell surface changes of <0.04 μm 2 , corresponding to vesicles of <110 nm diameter. Often downward steps followed upward steps within seconds, and vice versa, as if vesicles transiently opened and closed their lumen to the external space. Transient openings and closings sometimes alternated rhythmically for tens of seconds. The kinase inhibitor staurosporine dramatically increased the occurrence of such rhythmic episodes by making vesicle closure incomplete and by inhibiting fission. Staurosporine also promoted transient closures of large endocytic vesicles possibly representing remnants of secretory granules. We suggest that staurosporine blocks a late step in the endocytosis of both small and large vesicles, and that endocytosis involves a reaction cascade that can act as a chemical oscillator.