title: An RNA molecule that specifically inhibits G-protein-coupled receptor kinase 2 in vitro.
abstract: G-protein-coupled receptors are desensitized by a two-step process. In a first step, G-protein-coupled receptor kinases (GRKs) phosphorylate agonist-activated receptors that subsequently bind to a second class of proteins, the arrestins. GRKs can be classified into three subfamilies, which have been implicated in various diseases. The physiological role(s) of GRKs have been difficult to study as selective inhibitors are not available. We have used SELEX (systematic evolution of ligands by exponential enrichment) to develop RNA aptamers that potently and selectively inhibit GRK2. This process has yielded an aptamer, C13, which bound to GRK2 with a high affinity and inhibited GRK2-catalyzed rhodopsin phosphorylation with an IC50 of 4.1 nM. Phosphorylation of rhodopsin catalyzed by GRK5 was also inhibited, albeit with 20-fold lower potency (IC50 of 79 nM). Furthermore, C13 reveals significant specificity, since almost no inhibitory activity was detectable testing it against a panel of 14 other kinases. The aptamer is two orders of magnitude more potent than the best GRK2 inhibitors described previously and shows high selectivity for the GRK family of protein kinases.
authors.affiliation: Life and Medical Sciences Bonn, Program Unit Chemical Biology, c/o Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany. gmayer@uni-bonn.de
authors.forename: Günter
authors.initials: G
authors.lastname: Mayer
authors.forename: Bernhard
authors.initials: B
authors.lastname: Wulffen
authors.forename: Christian
authors.initials: C
authors.lastname: Huber
authors.forename: Jörg
authors.initials: J
authors.lastname: Brockmann
authors.forename: Birgit
authors.initials: B
authors.lastname: Flicke
authors.forename: Lars
authors.initials: L
authors.lastname: Neumann
authors.forename: Doris
authors.initials: D
authors.lastname: Hafenbradl
authors.forename: Bert M
authors.initials: BM
authors.lastname: Klebl
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Lohse
authors.forename: Cornelius
authors.initials: C
authors.lastname: Krasel
authors.forename: Michael
authors.initials: M
authors.lastname: Blind
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D054769:G-Protein-Coupled Receptor Kinase 2 / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D017434:Protein Structure, Tertiary; D012313:RNA / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D052156:SELEX Aptamer Technique
chemical_list: D052157:Aptamers, Nucleotide; D017931:DNA Primers; D004791:Enzyme Inhibitors; D011994:Recombinant Proteins; D012313:RNA; C496567:GRK2 protein, human; D054769:G-Protein-Coupled Receptor Kinase 2