Distinct Molecular Bases for pH Sensitivity of the Guard Cell K+ Channels KST1 and KAT1
نویسندگان
چکیده
منابع مشابه
Molecular determinants for the distinct pH sensitivity of Kir1.1 and Kir4.1 channels.
Kir1.1 (ROMK1) is inhibited by hypercapnia and intracellular acidosis with midpoint pH for channel inhibition (pK(a)) of approximately 6.7. Another close relative, Kir4.1 (BIR10), is also pH sensitive with much lower pH sensitivity (pK(a) approximately 6. 0), although it shares a high sequence homology with Kir1.1. To find the molecular determinants for the distinct pH sensitivity, we studied t...
متن کاملExternal pH effects on the depolarization-activated K channels in guard cell protoplasts of Vicia faba
Previous studies reveal that the pH of the apoplastic solution in the guard cell walls may vary between 7.2 and 5.1 in closed and open stomata, respectively. During these aperture and pH changes, massive K+ fluxes cross the cellular plasma membrane driving the osmotic turgor and volume changes of guard cells. Therefore, we examined the effect of extracellular pH on the depolarization-activated ...
متن کاملK+ channels of stomatal guard cells. Characteristics of the inward rectifier and its control by pH
Intracellular microelectrode recordings and a two-electrode voltage clamp have been used to characterize the current carried by inward rectifying K+ channels of stomatal guard cells from the broadbean, Vicia faba L. Superficially, the current displayed many features common to inward rectifiers of neuromuscular and egg cell membranes. In millimolar external K+ concentrations (Ko+), it activated ...
متن کاملVoltage dependence of K channels in guard-cell protoplasts.
Stomatal pores in leaves enable plants to regulate the exchange of gases with their environment. Variations of the pore aperture are mediated by controlled changes of potassium salt concentrations in the surrounding guard cells. The voltage-dependent gating of K(+)-selective channels in the plasma membrane (plasmalemma) of cell-wall-free guard cells (protoplasts) was studied at the molecular le...
متن کاملMolecular basis of plant-specific acid activation of K+ uptake channels.
During stomatal opening potassium uptake into guard cells and K+ channel activation is tightly coupled to proton extrusion. The pH sensor of the K+ uptake channel in these motor cells has, however, not yet been identified. Electrophysiological investigations on the voltage-gated, inward rectifying K+ channel in guard cell protoplasts from Solanum tuberosum (KST1), and the kst1 gene product expr...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1999
ISSN: 0021-9258
DOI: 10.1074/jbc.274.17.11599