Binding of 'AT4 receptor' ligands to insulin regulated aminopeptidase (IRAP) in intact Chinese hamster ovary cells
| Autor: | Aneta Lukaszuk, Dirk Tourwé, Paul R. Gard, Georges Vauquelin, Erzsébet Szemenyei, Jean-Paul De Backer, Heidi Demaegdt, Géza Tóth |
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| Přispěvatelé: | Molecular and Biochemical Pharmacology, Chemistry, Department of Bio-engineering Sciences, Organic Chemistry |
| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
radioligand binding
Endosome Peptidomimetic media_common.quotation_subject Cell Biology Ligands Biochemistry Binding Competitive 03 medical and health sciences Hemoglobins Radioligand Assay 0302 clinical medicine Endocrinology Cricetulus In vivo Cricetinae IRAP medicine Animals Humans Cystinyl Aminopeptidase Endocytotic Process Receptor Internalization Molecular Biology 030304 developmental biology media_common 0303 health sciences Ang IV Chinese hamster ovary cell Angiotensin II CHO cells Peptide Fragments internalization Protein Transport medicine.anatomical_structure HEK293 Cells Peptidomimetics AL-11 030217 neurology & neurosurgery Protein Binding |
| Popis: | Insulin regulated aminopeptidase (IRAP) recognises "AT(4)-receptor" ligands like angiotensin IV (Ang IV) and peptidomimetics like AL-11. The metabolic stability and high affinity of [(3)H]AL-11 for catalytically active IRAP allowed its detection in Chinese hamster ovary (CHO-K1) cell membranes in the absence of chelators (Demaegdt et al., 2009). Here, we show that, contrary to [(3)H]Ang IV, [(3)H]AL-11 displays high affinity and specificity for IRAP in intact CHO-K1 cells as well. After binding to IRAP at the surface, [(3)H]AL-11 is effectively internalized by an endocytotic process. Unexpectedly, surface binding and internalization of [(3)H]AL-11 was not affected by pretreating the cells with Ang IV but declined with AL-11. In the latter case surface expression of IRAP even increased. After elimination of simpler explanations, it is proposed that metabolically stable "AT(4)-receptor" ligands undergo semi-continuous cycling between the cell surface and endosomal compartments. The in vivo efficacy of stable and unstable "AT(4)-receptor" ligands could therefore differ. |
| Databáze: | OpenAIRE |
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