title: Angiotensin II-mediated cellular responses: a role for the 3'-untranslated region of the angiotensin AT1 receptor.
abstract: We have previously demonstrated that Chinese hamster ovary (CHO) cells transfected with the angiotensin II AT1 receptor gene containing only the coding region, presented tachyphylaxis to the total inositol phosphate (InsPs) and Ca2+ responses mediated by angiotensin II and [2-lysine]angiotensin II ([Lys2]angiotensin II). Now we have evaluated the possible role of the 3'-untranslated region of the angiotensin AT1 receptor mRNA in modulating the angiotensin AT1 receptor-mediated cellular responses. The binding parameters, as well as the Ca2+ and InsPs responses induced by angiotensin II and [Lys2]angiotensin II were similar in cells transfected with the angiotensin AT1 receptor with or without the 3'-untranslated region sequence. In cells transfected with the receptor containing the 3'-untranslated region sequence, angiotensin II-induced Ca2+ and InsPs responses were desensitized by repeated stimulations, whereas [Lys2]angiotensin II caused desensitization of InsPs production but not of Ca2+ uptake in these cells. Our results suggest that the 3'-untranslated region plays a role in modulating cell signalling involved in the tachyphylaxis of angiotensin AT1 receptor-mediated Ca2+ responses.
authors.affiliation: Department of Biophysics, Universidade Federal de São Paulo-Escola Paulista de Medicina, Rua Botucatu 862, 04023-060, São Paulo, SP, Brazil.
authors.forename: Lucimar P
authors.initials: LP
authors.lastname: França
authors.forename: Nelson A S
authors.initials: NA
authors.lastname: Pacheco
authors.forename: Silvana A A
authors.initials: SA
authors.lastname: Correa
authors.forename: Sang W
authors.initials: SW
authors.lastname: Han
authors.forename: Clovis R
authors.initials: CR
authors.lastname: Nakaie
authors.forename: Antonio C M
authors.initials: AC
authors.lastname: Paiva
authors.forename: Suma I
authors.initials: SI
authors.lastname: Shimuta
mesh_terms: D020413:3' Untranslated Regions / Q000502:physiology*; D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D006224:Cricetinae; D007295:Inositol Phosphates / Q000096:biosynthesis; D051381:Rats; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D013618:Tachyphylaxis / Q000235:genetics / Q000502:physiology; D014162:Transfection
chemical_list: D020413:3' Untranslated Regions; D007295:Inositol Phosphates; D044140:Receptor, Angiotensin, Type 1; D000804:Angiotensin II; C058393:angiotensin II, Lys(2)-; D002118:Calcium