title: Factor XIIIA transglutaminase crosslinks AT1 receptor dimers of monocytes at the onset of atherosclerosis.
abstract: Many G protein-coupled receptors form dimers in cells. However, underlying mechanisms are barely understood. We report here that intracellular factor XIIIA transglutaminase crosslinks agonist-induced AT1 receptor homodimers via glutamine315 in the carboxyl-terminal tail of the AT1 receptor. The crosslinked dimers displayed enhanced signaling and desensitization in vitro and in vivo. Inhibition of angiotensin II release or of factor XIIIA activity prevented formation of crosslinked AT1 receptor dimers. In agreement with this finding, factor XIIIA-deficient individuals lacked crosslinked AT1 dimers. Elevated levels of crosslinked AT1 dimers were present on monocytes of patients with the common atherogenic risk factor hypertension and correlated with an enhanced angiotensin II-dependent monocyte adhesion to endothelial cells. Elevated levels of crosslinked AT1 receptor dimers on monocytes could sustain the process of atherogenesis, because inhibition of angiotensin II generation or of intracellular factor XIIIA activity suppressed the appearance of crosslinked AT1 receptors and symptoms of atherosclerosis in ApoE-deficient mice.
authors.affiliation: Heinrich-Pette-Institut, Martinistrasse 52, D-20251 Hamburg, Germany.
authors.forename: Said
authors.initials: S
authors.lastname: AbdAlla
authors.forename: Heinz
authors.initials: H
authors.lastname: Lother
authors.forename: Andreas
authors.initials: A
authors.lastname: Langer
authors.forename: Yasser
authors.initials: Y
authors.lastname: el Faramawy
authors.forename: Ursula
authors.initials: U
authors.lastname: Quitterer
mesh_terms: D000804:Angiotensin II / Q000378:metabolism*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D001057:Apolipoproteins E / Q000172:deficiency / Q000235:genetics; D001161:Arteriosclerosis / Q000188:drug therapy / Q000378:metabolism*; D019281:Dimerization; D026122:Factor XIIIa / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005973:Glutamine / Q000378:metabolism; D006801:Humans; D051379:Mice; D009000:Monocytes / Q000378:metabolism; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism*; D012084:Renin-Angiotensin System / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D001057:Apolipoproteins E; D044140:Receptor, Angiotensin, Type 1; D005973:Glutamine; D000804:Angiotensin II; D026122:Factor XIIIa; D007703:Peptidyl-Dipeptidase A