title: Regulatory mechanisms underlying GKR2 levels in U937 cells: evidence for GRK3 involvement.
abstract: G protein-coupled receptors represent the most diverse group of proteins involved in transmembrane signalling, that participate in the regulation of a wide range of physicochemical messengers through the interaction with heterotrimeric G proteins. In addition, GPCRs stimulation also triggers a negative feedback mechanism, known as desensitization that prevents the potentially harmful effects caused by persistent receptor stimulation. In this adaptative response, G protein-coupled receptor kinases (GRKs) play a key role and alterations in their function are related to diverse pathophysiological situations. Based on the scarce knowledge about the regulation of GRK2 by other kinases of the same family, the aim of the present work was to investigate the regulation of GRK2 levels in systems where other GRKs are diminished by antisense technique. Present findings show that in U937 cells GRK2 levels are regulated by GRK3 and not by GRK6 through a mechanism involving InsP upregulation. This work reports a novel GRK3-mediated GRK2 regulatory mechanism and further suggests that GRK2 may also act as a compensatory kinase tending to counterbalance the reduction in GRK3 levels. This study provides the first evidence for the existence of GRKs cross-regulation.
authors: Laboratorio de Radioisótopos, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina. natfer@dna.uba.ar
authors: Natalia
authors: N
authors: Fernandez
authors: Federico
authors: F
authors: Monczor
authors: Maria R
authors: MR
authors: Tubio
authors: Carina
authors: C
authors: Shayo
authors: Carlos
authors: C
authors: Davio
mesh_terms: D054769:G-Protein-Coupled Receptor Kinase 2; D054770:G-Protein-Coupled Receptor Kinase 3; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D020320:Oligoribonucleotides, Antisense / Q000378:metabolism / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology; D020298:U937 Cells; D051552:beta-Adrenergic Receptor Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*
chemical_list: D020320:Oligoribonucleotides, Antisense; D054770:G-Protein-Coupled Receptor Kinase 3; C496567:GRK2 protein, human; C517848:GRK3 protein, human; D051552:beta-Adrenergic Receptor Kinases; D054769:G-Protein-Coupled Receptor Kinase 2