| Structural highlights
Function
[AKT1_ARATH] Highly selective inward-rectifying potassium channel that mediate potassium uptake by plant roots in response to low K(+) conditions, by a calcium-, CBL-, and CIPK-dependent pathway. Positively regulated by phosphorylation by CIPK23. Negatively regulated by a kinase-independent regulatory mechanism involving a competing direct binding of CBL10. Involved in the stomatal regulation by monitoring the turgor pressure in guard cells. Assuming opened or closed conformations in response to the voltage difference across the membrane, the channel is activated by hyperpolarization. May interact with the cytoskeleton or with regulatory proteins.[1] [2] [3] [4] [5]
Publication Abstract from PubMed
Plants obtain nutrients from the soil via transmembrane transporters and channels in their root hairs, from which ions radially transport in toward the xylem for distribution across the plant body. We determined structures of the hyperpolarization-activated channel AKT1 from Arabidopsis thaliana, which mediates K(+) uptake from the soil into plant roots. These structures of AtAKT1 embedded in lipid nanodiscs show that the channel undergoes a reduction of C4 to C2 symmetry, possibly to regulate its electrical activation.
Symmetry Reduction in a Hyperpolarization-Activated Homotetrameric Ion Channel.,Dickinson MS, Pourmal S, Gupta M, Bi M, Stroud RM Biochemistry. 2021 Dec 29. doi: 10.1021/acs.biochem.1c00654. PMID:34964607[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Pilot G, Gaymard F, Mouline K, Cherel I, Sentenac H. Regulated expression of Arabidopsis shaker K+ channel genes involved in K+ uptake and distribution in the plant. Plant Mol Biol. 2003 Mar;51(5):773-87. PMID:12678562
- ↑ Xu J, Li HD, Chen LQ, Wang Y, Liu LL, He L, Wu WH. A protein kinase, interacting with two calcineurin B-like proteins, regulates K+ transporter AKT1 in Arabidopsis. Cell. 2006 Jun 30;125(7):1347-60. PMID:16814720 doi:http://dx.doi.org/S0092-8674(06)00769-0
- ↑ Li L, Kim BG, Cheong YH, Pandey GK, Luan S. A Ca(2)+ signaling pathway regulates a K(+) channel for low-K response in Arabidopsis. Proc Natl Acad Sci U S A. 2006 Aug 15;103(33):12625-30. Epub 2006 Aug 8. PMID:16895985 doi:http://dx.doi.org/0605129103
- ↑ Lee SC, Lan WZ, Kim BG, Li L, Cheong YH, Pandey GK, Lu G, Buchanan BB, Luan S. A protein phosphorylation/dephosphorylation network regulates a plant potassium channel. Proc Natl Acad Sci U S A. 2007 Oct 2;104(40):15959-64. Epub 2007 Sep 26. PMID:17898163 doi:http://dx.doi.org/0707912104
- ↑ Hirsch RE, Lewis BD, Spalding EP, Sussman MR. A role for the AKT1 potassium channel in plant nutrition. Science. 1998 May 8;280(5365):918-21. PMID:9572739
- ↑ Dickinson MS, Pourmal S, Gupta M, Bi M, Stroud RM. Symmetry Reduction in a Hyperpolarization-Activated Homotetrameric Ion Channel. Biochemistry. 2021 Dec 29. doi: 10.1021/acs.biochem.1c00654. PMID:34964607 doi:http://dx.doi.org/10.1021/acs.biochem.1c00654
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