Rice Two-Pore K+ Channels Are Expressed in Different Types of Vacuoles
| Autor: | Jean-Charles Isner, Frans J. M. Maathuis, Stanislav Isayenkov |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Potassium Channels
Molecular Sequence Data Arabidopsis Sequence alignment Plant Science Vacuole Biology Gene Knockout Techniques chemistry.chemical_compound Gene Expression Regulation Plant Tobacco Protein Isoforms Amino Acid Sequence Lytic vacuole Research Articles Cellular localization Ion channel Plant Proteins Brefeldin A Oryza Cell Biology Cell biology Transport protein Protein Transport Membrane protein chemistry Biochemistry Vacuoles Mutagenesis Site-Directed Potassium Sequence Alignment |
| Zdroj: | The Plant Cell. 23:756-768 |
| ISSN: | 1532-298X 1040-4651 |
| DOI: | 10.1105/tpc.110.081463 |
| Popis: | Potassium (K+) is a major nutrient for plant growth and development. Vacuolar K+ ion channels of the two-pore K+ (TPK) family play an important role in maintaining K+ homeostasis. Several TPK channels were previously shown to be expressed in the lytic vacuole (LV) tonoplast. Plants also contain smaller protein storage vacuoles (PSVs) that contain membrane transporters. However, the mechanisms that define how membrane proteins reach different vacuolar destinations are largely unknown. The Oryza sativa genome encodes two TPK isoforms (TPKa and TPKb) that have very similar sequences and are ubiquitously expressed. The electrophysiological properties of both TPKs were comparable, showing inward rectification and voltage independence. In spite of high levels of similarity in sequence and transport properties, the cellular localization of TPKa and TPKb channels was different, with TPKa localization predominantly at the large LV and TPKb primarily in smaller PSV-type compartments. Trafficking of TPKa was sensitive to brefeldin A, while that of TPKb was not. The use of TPKa:TPKb chimeras showed that C-terminal domains are crucial for the differential targeting of TPKa and TPKb. Site-directed mutagenesis of C-terminal residues that were different between TPKa and TPKb identified three amino acids that are important in determining ultimate vacuolar destination. |
| Databáze: | OpenAIRE |
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