Characterization of RNA‐binding proteins possibly involved in modulating human AT₁ receptor mRNA stability

Abstract

Angiotensin II exerts its cardiovascular effects mainly through the activation of AT(1) receptors. These receptors can be regulated at a post-transcriptional level, that is through the modulation of the mRNA stability. This regulation usually involves proteins which are able to bind the 3'UTR of the mRNA molecule. The experiments of the present paper were performed in order to characterize the RNA-binding proteins interacting with the hAT(1) receptor mRNA in human vascular smooth muscle cells. Immunoblot analysis allowed us to identify three different RNA-binding proteins, AUF1, HuR, and hnRNP A1. UV cross-linking and immunoprecipitation experiments demonstrated that AUF1 binds to the hAT(1)-receptor mRNA radiolabeled probes specifically, but in different ways in relation to the clinically important A/C gene polymorphism. Gel shift experiments using purified recombinant proteins confirmed the specificity of interaction of these proteins with the hAT(1)-receptor mRNA. In basal conditions the proteins were mainly located in the nuclei, but angiotensin II administration clearly induced their translocation to the cytosol. This observation was confirmed by transfection experiments using both GFP/AUF1 and GFP/HuR fusion proteins. Our findings allow identification of specific RNA-binding proteins possibly involved in the control of the hAT1-receptor mRNA stability and in the regulation of their expressions.

Association of Angiotensin II Type 1 Receptor (A1166C) Gene Polymorphism and Its Increased Expression in Essential Hypertension: A Case-Control Study

“…In a separate study, an elevated level of AT1R gene expression in the brainstem of spontaneously hypertensive rat was observed [37]. The transcriptional activity and mRNA stability of AT1R gene is regulated by specific RNA-binding proteins [38]. The role of AT1R protein expression in the regulation of blood pressure has been reported in recent studies [39]–[40].…”

Effect of chronic contractile activity on mRNA stability in skeletal muscle

“…In contrast, the AUF1 proteins have been shown to bind to and destabilize the mRNAs encoding human angiotensin 1 receptor (47), sarcoendoplasmic reticulum calcium ATPase2a (5), and the calcitonin receptor (69). Furthermore, HuR and AUF1 have common targets, and growing evidence has demonstrated that homomultimerization of HuR and AUF1 can bind simultaneously and competitively to a single ARE (32,47,69). Interestingly, both HuR and the AUF1 proteins target the ARE in the c-myc 3=-UTR (18,31).…”

hnRNP A1 regulates UV-induced NF-κB signalling through destabilization of cIAP1 mRNA

“…hnRNP A1 is a multifunctional protein that is implicated in diverse steps of RNA metabolism including splicing, 24 mRNA stability 25 and translation. 17 hnRNP A1 has been previously shown to bind several labile mRNAs that contain the AUUUA sequence, including the granulocyte-macrophage colony-stimulating factor (GM-CSF), 25 human angiotensin receptor AT 1 , 26 and cytochromes P450, 2A6 and 2A5. 27,28 A similar AUUUA sequence is found in ARE no.…”