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Ca(2)+-stimulated exocytosis in maize coleoptile cells.

Sutter, J. U. and Homann, Ulrike and Thiel, Gerhard (2000):
Ca(2)+-stimulated exocytosis in maize coleoptile cells.
In: The Plant cell, pp. 1127-36, 12, (7), ISSN 1040-4651, [Article]

Abstract

Changes in membrane capacitance (C(m)) after photolysis of the caged Ca(2)+ compound dimethoxynitrophenamine were studied in protoplasts from maize coleoptiles. Changes in C(m) values resulting from increased concentrations of free Ca(2)+ in the cytoplasm ([Ca(2)+](cyt)) were interpreted as representing changes in [Ca(2)+](cyt)-sensitive exocytosis and endocytosis. A continuous increase in [Ca(2)+](cyt) resulted in a sigmoidal increase in C(m) values with a half-maximal concentration at approximately 1 microM. The steep increase in C(m) values was followed by a variable slow phase in changing C(m) values. When [Ca(2)+](cyt) increased at a rate of 0.6 micromol L(-)(1) sec(-)(1), the initial steep increase in C(m) values lasted approximately 5 to 10 sec. During this time, protoplasts increased in surface area by approximately 2.5%. The biphasic dynamics of [Ca(2)+](cyt)-stimulated increases in C(m) values can be described by a kinetic model containing two pools of vesicles with two [Ca(2)+](cyt)-sensitive steps in the exocytotic pathway.

Item Type: Article
Erschienen: 2000
Creators: Sutter, J. U. and Homann, Ulrike and Thiel, Gerhard
Title: Ca(2)+-stimulated exocytosis in maize coleoptile cells.
Language: English
Abstract:

Changes in membrane capacitance (C(m)) after photolysis of the caged Ca(2)+ compound dimethoxynitrophenamine were studied in protoplasts from maize coleoptiles. Changes in C(m) values resulting from increased concentrations of free Ca(2)+ in the cytoplasm ([Ca(2)+](cyt)) were interpreted as representing changes in [Ca(2)+](cyt)-sensitive exocytosis and endocytosis. A continuous increase in [Ca(2)+](cyt) resulted in a sigmoidal increase in C(m) values with a half-maximal concentration at approximately 1 microM. The steep increase in C(m) values was followed by a variable slow phase in changing C(m) values. When [Ca(2)+](cyt) increased at a rate of 0.6 micromol L(-)(1) sec(-)(1), the initial steep increase in C(m) values lasted approximately 5 to 10 sec. During this time, protoplasts increased in surface area by approximately 2.5%. The biphasic dynamics of [Ca(2)+](cyt)-stimulated increases in C(m) values can be described by a kinetic model containing two pools of vesicles with two [Ca(2)+](cyt)-sensitive steps in the exocytotic pathway.

Journal or Publication Title: The Plant cell
Volume: 12
Number: 7
Divisions: 10 Department of Biology
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10 Department of Biology > Plant Membrane Biophysics
10 Department of Biology > Plant Cell Biology
Date Deposited: 22 Jun 2011 09:23
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