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The topology of plastid inner envelope potassium cation efflux antiporter KEA1 provides new insights into its regulatory features.
Photosynth Res. 2020 Jul; 145(1):43-54.PR

Abstract

The plastid potassium cation efflux antiporters (KEAs) are important for chloroplast function, development, and photosynthesis. To understand their regulation at the protein level is therefore of fundamental importance. Prior studies have focused on the regulatory K+ transport and NAD-binding (KTN) domain in the C-terminus of the thylakoid carrier KEA3 but the localization of this domain remains unclear. While all three plastid KEA members are highly conserved in their transmembrane region and the C-terminal KTN domain, only the inner envelope KEA family members KEA1 and KEA2 carry a long soluble N-terminus. Interestingly, this region is acetylated at lysine 168 by the stromal acetyltransferase enzyme NSI. If an odd number of transmembrane domains existed for inner envelope KEAs, as it was suggested for all three plastid KEA carriers, regulatory domains and consequently protein regulation would occur on opposing sides of the inner envelope. In this study we therefore set out to investigate the topology of inner envelope KEA proteins. Using a newly designed antibody specific to the envelope KEA1 N-terminus and transgenic Arabidopsis plants expressing a C-terminal KEA1-YFP fusion protein, we show that both, the N-terminal and C-terminal, regulatory domains of KEA1 reside in the chloroplast stroma and not in the intermembrane space. Considering the high homology between KEA1 and KEA2, we therefore reason that envelope KEAs must consist of an even number of transmembrane domains.

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Publisher Full Text (DOI)

Authors+Show Affiliations

Bölter B
Dept. I, Plant Biochemistry, Ludwig Maximilians University Munich, Groβhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany.
Mitterreiter MJ
Dept. I, Plant Biochemistry, Ludwig Maximilians University Munich, Groβhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany.
Schwenkert S
Dept. I, Plant Biochemistry, Ludwig Maximilians University Munich, Groβhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany.
Finkemeier I
Plant Physiology, Institute of Biology and Biotechnology of Plants, University of Muenster, Schlossplatz 7, 48149, Muenster, Germany.
Kunz HH
Plant Physiology, School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA, 99164-4236, USA. henning.kunz@wsu.edu.

MeSH

ArabidopsisArabidopsis ProteinsBiological TransportChloroplastsPhotosynthesisPlants, Genetically ModifiedPlastidsPotassiumPotassium-Hydrogen AntiportersThylakoids

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31865509

Citation

Bölter, Bettina, et al. "The Topology of Plastid Inner Envelope Potassium Cation Efflux Antiporter KEA1 Provides New Insights Into Its Regulatory Features." Photosynthesis Research, vol. 145, no. 1, 2020, pp. 43-54.
Bölter B, Mitterreiter MJ, Schwenkert S, et al. The topology of plastid inner envelope potassium cation efflux antiporter KEA1 provides new insights into its regulatory features. Photosynth Res. 2020;145(1):43-54.
Bölter, B., Mitterreiter, M. J., Schwenkert, S., Finkemeier, I., & Kunz, H. H. (2020). The topology of plastid inner envelope potassium cation efflux antiporter KEA1 provides new insights into its regulatory features. Photosynthesis Research, 145(1), 43-54. https://doi.org/10.1007/s11120-019-00700-2
Bölter B, et al. The Topology of Plastid Inner Envelope Potassium Cation Efflux Antiporter KEA1 Provides New Insights Into Its Regulatory Features. Photosynth Res. 2020;145(1):43-54. PubMed PMID: 31865509.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The topology of plastid inner envelope potassium cation efflux antiporter KEA1 provides new insights into its regulatory features. AU - Bölter,Bettina, AU - Mitterreiter,Melanie J, AU - Schwenkert,Serena, AU - Finkemeier,Iris, AU - Kunz,Hans-Henning, Y1 - 2019/12/21/ PY - 2019/07/04/received PY - 2019/12/11/accepted PY - 2019/12/23/pubmed PY - 2021/6/1/medline PY - 2019/12/23/entrez KW - Arabidopsis KW - Chloroplast KW - Photosynthesis KW - Protein regulation KW - Topology KW - Transporter SP - 43 EP - 54 JF - Photosynthesis research JO - Photosynth Res VL - 145 IS - 1 N2 - The plastid potassium cation efflux antiporters (KEAs) are important for chloroplast function, development, and photosynthesis. To understand their regulation at the protein level is therefore of fundamental importance. Prior studies have focused on the regulatory K+ transport and NAD-binding (KTN) domain in the C-terminus of the thylakoid carrier KEA3 but the localization of this domain remains unclear. While all three plastid KEA members are highly conserved in their transmembrane region and the C-terminal KTN domain, only the inner envelope KEA family members KEA1 and KEA2 carry a long soluble N-terminus. Interestingly, this region is acetylated at lysine 168 by the stromal acetyltransferase enzyme NSI. If an odd number of transmembrane domains existed for inner envelope KEAs, as it was suggested for all three plastid KEA carriers, regulatory domains and consequently protein regulation would occur on opposing sides of the inner envelope. In this study we therefore set out to investigate the topology of inner envelope KEA proteins. Using a newly designed antibody specific to the envelope KEA1 N-terminus and transgenic Arabidopsis plants expressing a C-terminal KEA1-YFP fusion protein, we show that both, the N-terminal and C-terminal, regulatory domains of KEA1 reside in the chloroplast stroma and not in the intermembrane space. Considering the high homology between KEA1 and KEA2, we therefore reason that envelope KEAs must consist of an even number of transmembrane domains. SN - 1573-5079 UR - https://www.unboundmedicine.com/medline/citation/31865509/The_topology_of_plastid_inner_envelope_potassium_cation_efflux_antiporter_KEA1_provides_new_insights_into_its_regulatory_features_ DB - PRIME DP - Unbound Medicine ER -