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Actin Dynamics Regulates Voltage‐Dependent Calcium‐Permeable Channels of the Vicia faba Guard Cell Plasma Membrane
Author(s) -
Zhang Wei,
Fan LiuMin
Publication year - 2009
Publication title -
journal of integrative plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.734
H-Index - 83
eISSN - 1744-7909
pISSN - 1672-9072
DOI - 10.1111/j.1744-7909.2009.00859.x
Subject(s) - guard cell , biophysics , stretch activated ion channel , chemistry , t type calcium channel , actin , cytochalasin d , membrane potential , voltage dependent calcium channel , cardiac action potential , second messenger system , microbiology and biotechnology , calcium , biology , biochemistry , cytoskeleton , repolarization , cell , signal transduction , electrophysiology , organic chemistry , neuroscience
Free cytosolic Ca 2+ ([Ca 2+ ] cyt ) is an ubiquitous second messenger in plant cell signaling, and [Ca 2+ ] cyt elevation is associated with Ca 2+ ‐permeable channels in the plasma membrane and endomembranes regulated by a wide range of stimuli. However, knowledge regarding Ca 2+ channels and their regulation remains limited in planta . A type of voltage‐dependent Ca 2+ ‐permeable channel was identified and characterized for the Vicia faba L. guard cell plasma membrane by using patch‐clamp techniques. These channels are permeable to both Ba 2+ and Ca 2+ , and their activities can be inhibited by micromolar Gd 3+ . The unitary conductance and the reversal potential of the channels depend on the Ca 2+ or Ba 2+ gradients across the plasma membrane. The inward whole‐cell Ca 2+ (Ba 2+ ) current, as well as the unitary current amplitude and NP o of the single Ca 2+ channel, increase along with the membrane hyperpolarization. Pharmacological experiments suggest that actin dynamics may serve as an upstream regulator of this type of calcium channel of the guard cell plasma membrane. Cytochalasin D, an actin polymerization blocker, activated the NPo of these channels at the single channel level and increased the current amplitude at the whole‐cell level. But these channel activations and current increments could be restrained by pretreatment with an F‐actin stabilizer, phalloidin. The potential physiological significance of this regulatory mechanism is also discussed.