RT Journal Article T1 Functional Complexes of Angiotensin-Converting Enzyme 2 and Renin-Angiotensin System Receptors: Expression in Adult but Not Fetal Lung Tissue A1 Franco, Rafael A1 Lillo, Alejandro A1 Rivas Santisteban, Rafael A1 Rodríguez Pérez, Ana Isabel A1 Reyes Resina, Irene A1 Labandeira García, José Luis A1 Navarro, Gemma K1 COVID-19 K1 SARS-CoV-2 receptor K1 RAS K1 ACE2 K1 Angiotensin receptor K1 Mas receptor K1 Lung AB Angiotensin-converting enzyme 2 (ACE2) is a membrane peptidase and a component of the renin-angiotensin system (RAS) that has been found in cells of all organs, including the lungs. While ACE2 has been identified as the receptor for severe acute respiratory syndrome (SARS) coronaviruses, the mechanism underlying cell entry remains unknown. Human immunodeficiency virus infects target cells via CXC chemokine receptor 4 (CXCR4)-mediated endocytosis. Furthermore, CXCR4 interacts with dipeptidyl peptidase-4 (CD26/DPPIV), an enzyme that cleaves CXCL12/SDF-1, which is the chemokine that activates this receptor. By analogy, we hypothesized that ACE2 might also be capable of interactions with RAS-associated G-protein coupled receptors. Using resonance energy transfer and cAMP and mitogen-activated protein kinase signaling assays, we found that human ACE2 interacts with RAS-related receptors, namely the angiotensin II type 1 receptor (AT1R), the angiotensin II type 2 receptor (AT2R), and the MAS1 oncogene receptor (MasR). Although these interactions led to various alterations of signal transduction, but, more importantly, ligand binding to AT1R resulted in the downregulation of ACE2 cell surface expression, while ligand binding to AT2R, but not to MasR, resulted in upregulation of ACE2 cell surface expression. Proximity ligation assays performed in situ revealed macromolecular complexes containing ACE2 and AT1R, AT2R or MasR in adult but not fetal mouse lung tissue. These findings highlight the relevance of RAS in SARS-CoV-2 infection and the role of ACE2-containing complexes as potential therapeutic targets PB MDPI YR 2020 FD 2020 LK http://hdl.handle.net/10347/24202 UL http://hdl.handle.net/10347/24202 LA eng NO Franco, R.; Lillo, A.; Rivas-Santisteban, R.; Rodríguez-Pérez, A.I.; Reyes-Resina, I.; Labandeira-García, J.L.; Navarro, G. Functional Complexes of Angiotensin-Converting Enzyme 2 and Renin-Angiotensin System Receptors: Expression in Adult but Not Fetal Lung Tissue. Int. J. Mol. Sci. 2020, 21, 9602 NO The Molecular Neurobiology Laboratory of the University of Barcelona is considered a research group of excellence by the Regional Catalonian Government (grup consolidat #2017 SGR 1497) DS Minerva RD 30 abr 2026