The PKC-ζ pseudosubstrate peptide induces glutamate release from retinal pigment epithelium cells through kinase- independent activation of Best1
| Autor: | Alejandro Alvarez-Arce, Ana María López-Colomé, Edith López, Irene Lee-Rivera |
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| Rok vydání: | 2021 |
| Předmět: |
0301 basic medicine
Glutamic Acid Retinal Pigment Epithelium 030226 pharmacology & pharmacy General Biochemistry Genetics and Molecular Biology 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine medicine Animals Rats Long-Evans Bestrophins General Pharmacology Toxicology and Pharmaceutics Kinase activity Cells Cultured Protein Kinase C Protein kinase C Retinal pigment epithelium Dose-Response Relationship Drug biology Kinase Glutamate receptor General Medicine Rats Cell biology 030104 developmental biology medicine.anatomical_structure Bestrophin 1 chemistry Ionomycin biology.protein Phosphorylation sense organs Peptides |
| Zdroj: | Life Sciences. 265:118860 |
| ISSN: | 0024-3205 |
| DOI: | 10.1016/j.lfs.2020.118860 |
| Popis: | Aims The retinal pigment epithelium (RPE) is a highly specialized cell monolayer, that plays a key role in the maintenance of photoreceptor function and the blood-retina barrier (BRB). In this study, we found that a myristoylated pseudosubstrate of PKC-ζ (PKCζ PS), considered as a PKC-ζ inhibitor, plays a distinct role in RPE. Main methods We demonstrated that PKCζ PS stimulates the release of Glutamate (Glu) using in vitro 3H-Glutamate release experiments. By western blot, kinase assays, and Fluoresence Ca+2 Concentration Measurements, we determined the cellular mechanisms involved in such release. Key findings Surprisingly, PKCζ PS has no effect on either phosphorylation of T560, essential for catalytic activity, nor it has an effect on kinase activity. It induces the dose-dependent release of Glu by increasing intracellular Ca+2 levels. Interestingly, this release was not observed upon stimulation by other non-competitive PKC-ζ inhibitors. We here demonstrated that the PKCζ PS stimulates the release of Glutamate from RPE by activating the Ca2+-dependent Cl channel Bestrophin 1 (Best1). Significance These results question PKCζ PS specificity as an inhibitor of this enzyme. Furthermore, the present results underline the relevance of clarifying the molecular mechanisms involved in glutamate release from the retina under conditions derived from excitotoxic stimuli. |
| Databáze: | OpenAIRE |
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