14-3-3 proteins modulate the plant inward rectifier K+ channel KAT1 heterologously expressed in Xenopus oocytes. Injection of recombinant plant 14-3-3 proteins into oocytes shifted the activation curve of KAT1 by +11 mV and increased the τon. KAT1 was also modulated by 14-3-3 proteins of Xenopus oocytes. Titration of the endogenous 14-3-3 proteins by injection of the peptide Raf 621p resulted in a strong decrease in KAT1 current (∼70% at -150 mV). The mutation K56E performed on plant protein 14-3-3 in a highly conserved recognition site prevented channel activation. Because the maximal conductance of KAT1 was unaffected by 14-3-3, we can exclude that they act by increasing the number of channels, thus ruling out any effect of these proteins on channel trafficking and/or insertion into the oocyte membrane. 14-3-3 proteins also increased KAT1 current in inside-out patches, suggesting a direct interaction with the channel. Direct interaction was confirmed by overlay experiments with radioactive 14-3-3 on oocyte membranes expressing KAT1.
The potassium channel KAT1 is activated by plant and animal 14-3-3 proteins / B. Sottocornola, S. Visconti, S. Orsi, S. Gazzarrini, S. Giacometti, C. Olivari, L. Camoni, P. Aducci, M. Marra, A. Abenavoli, G. Thiel, A. Moroni. - In: THE JOURNAL OF BIOLOGICAL CHEMISTRY. - ISSN 0021-9258. - 281:47(2006), pp. 35735-35741.
|Titolo:||The potassium channel KAT1 is activated by plant and animal 14-3-3 proteins|
MORONI, ANNA (Ultimo)
|Settore Scientifico Disciplinare:||Settore BIO/04 - Fisiologia Vegetale|
|Data di pubblicazione:||2006|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1074/jbc.M603361200|
|Appare nelle tipologie:||01 - Articolo su periodico|