Functional rescue of a defective angiotensin II AT1 receptor mutant by the Mas protooncogene

• Published in: Regulatory peptides Vol. 141; no. 1-3; pp. 159 - 167
• Main Authors: SANTOS, Edson L, REIS, Rosana I, COSTA-NETO, Claudio M, PESQUERO, Joao B, SILVA, Ronaldo G, SHIMUTA, Suma I, PECHER, Christiane, BASCANDS, Jean-Loup, SCHANSTRA, Joost P, OLIVEIRA, Laerte, BADER, Michael, PAIV, Antonio C. M
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier 07-06-2007; Amsterdam
• Subjects: Amino Acid Sequence; Angiotensin II; Angiotensin II - metabolism; Animals; Biological and medical sciences; Cell Membrane; Cell Membrane - metabolism; Cercopithecus aethiops; CHO Cells; COS Cells; Cricetinae; Cricetulus; Fluoresceins; Fluorescent Antibody Technique, Direct; Fluorescent Dyes; Fundamental and applied biological sciences. Psychology; Indoles; Inhibitory Concentration 50; Inositol Phosphates; Inositol Phosphates - analysis; Inositol Phosphates - metabolism; Models, Chemical; Molecular Sequence Data; Mutation; Polymerase Chain Reaction; Proto-Oncogenes; Proto-Oncogenes - genetics; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 1 - chemistry; Receptor, Angiotensin, Type 1 - genetics; Receptor, Angiotensin, Type 1 - metabolism; Receptors, G-Protein-Coupled; Receptors, G-Protein-Coupled - genetics; Receptors, G-Protein-Coupled - metabolism; Transfection; Vertebrates: endocrinology; Peptide hormone; G-protein-coupled receptor; AT1 angiotensin receptor; AT1 receptor; Octapeptide; Renin angiotensin system; Mas protooncogene; Mutation; Angiotensin II; Dimerization; Protooncogene; G protein; Biological receptor
• DOI: 10.1016/j.regpep.2006.12.030
• EISSN: 1873-1686
• ISSN: 0167-0115

Earlier studies with Mas protooncogene, a member of the G-protein-coupled receptor family, have proposed this gene to code for a functional AngII receptor, however further results did not confirm this assumption. In this work we investigated the hypothesis that a heterodimeration AT(1)/Mas could result in a functional interaction between both receptors. For this purpose, CHO or COS-7 cells were transfected with the wild-type AT(1) receptor, a non-functional AT(1) receptor double mutant (C18F-K20A) and Mas or with WT/Mas and C18F-K20A/Mas. Cells single-expressing Mas or C18F/K20A did not show any binding for AngII. The co-expression of the wild-type AT(1) receptor and Mas showed a binding profile similar to that observed for the wild-type AT(1) expressed alone. Surprisingly, the co-expression of the double mutant C18F/K20A and Mas evoked a total recovery of the binding affinity for AngII to a level similar to that obtained for the wild-type AT(1). Functional measurements using inositol phosphate and extracellular acidification rate assays also showed a clear recovery of activity for AngII on cells co-expressing the mutant C18F/K20A and Mas. In addition, immunofluorescence analysis localized the AT(1) receptor mainly at the plasma membrane and the mutant C18F-K20A exclusively inside the cells. However, the co-expression of C18F-K20A mutant with the Mas changed the distribution pattern of the mutant, with intense signals at the plasma membrane, comparable to those observed in cells expressing the wild-type AT(1) receptor. These results support the hypothesis that Mas is able to rescue binding and functionality of the defective C18F-K20A mutant by dimerization.