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A transient outward-rectifying K+ channel current down-regulated by cytosolic Ca2+ in Arabidopsis thaliana guard cells

Publication ,  Journal Article
Pei, ZM; Baizabal-Aguirre, VM; Allen, GJ; Schroeder, JI
Published in: Proceedings of the National Academy of Sciences of the United States of America
May 26, 1998

Sustained (noninactivating) outward-rectifying K+ channel currents have been identified in a variety of plant cell types and species. Here, in Arabidopsis thaliana guard cells, in addition to these sustained K+ currents, an inactivating outward-rectifying K+ current was characterized (plant A-type current: IAP). IAP activated rapidly with a time constant of 165 ms and inactivated slowly with a time constant of 7.2 sec at +40 mV. IAP was enhanced by increasing the duration (from 0 to 20 sec) and degree (from +20 to -100 mV) of prepulse hyperpolarization. Ionic substitution and relaxation (tail) current recordings showed that outward IAP was mainly carried by K+ ions. In contrast to the sustained outward-rectifying K+ currents, cytosolic alkaline pH was found to inhibit IAP and extracellular K+ was required for IAP activity. Furthermore, increasing cytosolic free Ca2+ in the physiological range strongly inhibited IAP activity with a half inhibitory concentration of ≈ 94 nM. We present a detailed characterization of an inactivating K+ current in a higher plant cell. Regulation of IAP by diverse factors including membrane potential, cytosolic Ca2+ and pH, and extracellular K+ and Ca2+ implies that the inactivating IAP described here may have important functions during transient depolarizations found in guard cells, and in integrated signal transduction processes during stomatal movements.

Duke Scholars

Published In

Proceedings of the National Academy of Sciences of the United States of America

DOI

ISSN

0027-8424

Publication Date

May 26, 1998

Volume

95

Issue

11

Start / End Page

6548 / 6553
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Pei, Z. M., Baizabal-Aguirre, V. M., Allen, G. J., & Schroeder, J. I. (1998). A transient outward-rectifying K+ channel current down-regulated by cytosolic Ca2+ in Arabidopsis thaliana guard cells. Proceedings of the National Academy of Sciences of the United States of America, 95(11), 6548–6553. https://doi.org/10.1073/pnas.95.11.6548
Pei, Z. M., V. M. Baizabal-Aguirre, G. J. Allen, and J. I. Schroeder. “A transient outward-rectifying K+ channel current down-regulated by cytosolic Ca2+ in Arabidopsis thaliana guard cells.” Proceedings of the National Academy of Sciences of the United States of America 95, no. 11 (May 26, 1998): 6548–53. https://doi.org/10.1073/pnas.95.11.6548.
Pei ZM, Baizabal-Aguirre VM, Allen GJ, Schroeder JI. A transient outward-rectifying K+ channel current down-regulated by cytosolic Ca2+ in Arabidopsis thaliana guard cells. Proceedings of the National Academy of Sciences of the United States of America. 1998 May 26;95(11):6548–53.
Pei, Z. M., et al. “A transient outward-rectifying K+ channel current down-regulated by cytosolic Ca2+ in Arabidopsis thaliana guard cells.” Proceedings of the National Academy of Sciences of the United States of America, vol. 95, no. 11, May 1998, pp. 6548–53. Scopus, doi:10.1073/pnas.95.11.6548.
Pei ZM, Baizabal-Aguirre VM, Allen GJ, Schroeder JI. A transient outward-rectifying K+ channel current down-regulated by cytosolic Ca2+ in Arabidopsis thaliana guard cells. Proceedings of the National Academy of Sciences of the United States of America. 1998 May 26;95(11):6548–6553.
Journal cover image

Published In

Proceedings of the National Academy of Sciences of the United States of America

DOI

ISSN

0027-8424

Publication Date

May 26, 1998

Volume

95

Issue

11

Start / End Page

6548 / 6553