title: High-resolution membrane capacitance measurements for studying endocytosis and exocytosis in yeast.
abstract: Fusion of exocytotic vesicles with the plasma membrane gives rise to an increase in membrane surface area, whereas the surface area is decreased when vesicles are internalized during endocytosis. Changes in membrane surface area, resulting from fusion and fission of membrane vesicles, can be followed by monitoring the corresponding proportional changes in membrane capacitance. Using the cell-attached configuration of the patch-clamp techniques we were able to resolve the elementary processes of endo- and exocytosis in yeast protoplasts at high temporal and spatial resolution. Spontaneous capacitance changes were predominantly in the range of 0.2-1 fF which translates to vesicle diameters of 90-200 nm. The size distribution revealed that endocytotic vesicles with a median at about 132 nm were smaller than exocytotic vesicles with a median at 155 nm. In energized and metabolizing protoplasts, endo- and exocytotic events occurred at frequencies of 1.6 and 2.7 events per minute, respectively. Even though these numbers appear very low, they are in good agreement with the observed growth rate of yeast cells and protoplasts.
authors.affiliation: Technische Universität Darmstadt, Fachbereich Biologie, Schnittspahnstrasse 10, 64287 Darmstadt, Germany.
authors.forename: Lucia
authors.initials: L
authors.lastname: Carrillo
authors.affiliation: Technische Universität Darmstadt, Fachbereich Biologie, Schnittspahnstrasse 10, 64287 Darmstadt, Germany.
authors.forename: Bayram
authors.initials: B
authors.lastname: Cucu
authors.affiliation: Technische Universität Darmstadt, Fachbereich Biologie, Schnittspahnstrasse 10, 64287 Darmstadt, Germany.|Present address: INM-Leibniz-Institute for New Materials, Biomineralization, Campus D2 2, 66123 Saarbrücken, Germany.
authors.forename: Vera
authors.initials: V
authors.lastname: Bandmann
authors.affiliation: Technische Universität Darmstadt, Fachbereich Biologie, Schnittspahnstrasse 10, 64287 Darmstadt, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Homann
authors.affiliation: Technische Universität Darmstadt, Fachbereich Biologie, Schnittspahnstrasse 10, 64287 Darmstadt, Germany.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Hertel
authors.affiliation: Electron Microscopy Core Facility (EMCF), COS, Universität Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Hillmer
authors.affiliation: Technische Universität Darmstadt, Fachbereich Biologie, Schnittspahnstrasse 10, 64287 Darmstadt, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Thiel
authors.affiliation: Technische Universität Darmstadt, Fachbereich Biologie, Schnittspahnstrasse 10, 64287 Darmstadt, Germany.
authors.forename: Adam
authors.initials: A
authors.lastname: Bertl
mesh_terms: D002462:Cell Membrane / Q000378:metabolism* / Q000502:physiology; D004705:Endocytosis; D005089:Exocytosis; D008564:Membrane Potentials; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
keywords: endocytosis; exocytosis; membrane capacitance; protoplast; yeast