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Trafficking of the plant potassium inward rectifier KAT1 in guard cell protoplasts of Vicia faba
Author(s) -
Hurst Annette C.,
Meckel Tobias,
Tayefeh Sascha,
Thiel Gerhard,
Homann Ulrike
Publication year - 2004
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2003.01972.x
Subject(s) - guard cell , inward rectifier potassium ion channel , biophysics , vesicular transport protein , vesicle , microbiology and biotechnology , patch clamp , potassium channel , endocytosis , membrane , ion channel , vicia faba , biology , chemistry , biochemistry , cell , botany , receptor
Summary Trafficking of K + inward (K in + ) rectifying channels was analyzed in guard cells of Vicia faba transfected with the K in + rectifier from Arabidopsis thaliana KAT1 fused to the green fluorescent protein (GFP). Confocal images and whole‐cell patch‐clamp measurements confirmed the incorporation of active KAT1 channels into the plasma membrane of transfected guard cell protoplasts. The K in + rectifier current density of the plasma membrane was much larger in transfected protoplasts than in wild‐type (wt) protoplasts. This shows a coupling between K + channel synthesis and incorporation of the channel into the plasma membrane. Pressure‐driven increase and decrease in surface area led to the incorporation and removal of vesicular membrane carrying active K in + rectifier in wt and transfected protoplasts. These vesicular membranes revealed a higher channel density than the plasma membrane, suggesting that K in + rectifier remains in clusters during trafficking to and from the plasma membrane. The observed results can be explained by a model illustrating that vesicles of a pre‐plasma membrane pool carry K + channels preferentially in clusters during constitutive and pressure‐driven exo‐ and endocytosis.