Regulatory Aspects of the Vacuolar CAT2 Arginine Transporter of S. lycopersicum: Role of Osmotic Pressure and Cations
| Autor: | Cesare Indiveri, Mariafrancesca Scalise, Michele Galluccio, Teresa M.R. Regina, Jessica Cosco |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
0301 basic medicine Models Molecular osmolyte Arginine Molecular Conformation arginine Vacuole 01 natural sciences Catalysis Article Inorganic Chemistry lcsh:Chemistry 03 medical and health sciences Structure-Activity Relationship Osmotic Pressure Cations Extracellular Escherichia coli Osmotic pressure Amino acid transporter Physical and Theoretical Chemistry Cationic Amino Acid Transporter 2 Molecular Biology protein expression lcsh:QH301-705.5 Spectroscopy Dose-Response Relationship Drug vacuole Chemistry Organic Chemistry Cholesterol binding cholesterol Transporter Biological Transport General Medicine Hydrogen-Ion Concentration CRAC Recombinant Proteins Computer Science Applications 030104 developmental biology lcsh:Biology (General) lcsh:QD1-999 Osmolyte Liposomes Vacuoles transport Biophysics 010606 plant biology & botany |
| Zdroj: | International Journal of Molecular Sciences, Vol 20, Iss 4, p 906 (2019) International Journal of Molecular Sciences Volume 20 Issue 4 |
| ISSN: | 1422-0067 |
| Popis: | Many proteins are localized at the vacuolar membrane, but most of them are still poorly described, due to the inaccessibility of this membrane from the extracellular environment. This work focused on the characterization of the CAT2 transporter from S. lycopersicum (SlCAT2) that was previously overexpressed in E. coli and reconstituted in proteoliposomes for transport assay as [3H]Arg uptake. The orientation of the reconstituted transporter has been attempted and current data support the hypothesis that the protein is inserted in the liposome in the same orientation as in the vacuole. SlCAT2 activity was dependent on the pH, with an optimum at pH 7.5. SlCAT2 transport activity was stimulated by the increase of internal osmolality from 0 to 175 mOsmol while the activity was inhibited by the increase of external osmolality. K+, Na+, and Mg2+ present on the external side of proteoliposomes at physiological concentrations, inhibited the transport activity differently, the cations had no effect when included in the internal proteoliposome compartment. This data highlighted an asymmetric regulation of SlCAT2. Cholesteryl hemisuccinate, included in the proteoliposomal membrane, stimulated the SlCAT2 transport activity. The homology model of the protein was built using, as a template, the 3D structure of the amino acid transporter GkApcT. Putative substrate binding residues and cholesterol binding domains were proposed. Altogether, the described results open new perspectives for studying the response of SlCAT2 and, in general, of plant vacuolar transporters to metabolic and environmental changes. |
| Databáze: | OpenAIRE |
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