ININFA   02677
INSTITUTO DE INVESTIGACIONES FARMACOLOGICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Involvement of RGS domain of GRK2 in the desensitization of beta3-adrenergic receptor
Autor/es:
ECHEVERRIA E; DIAZ NEBREDA A; CABRERA M; DAVIO C; SHAYO C; FERNANDEZ N
Lugar:
San Carlos de Bariloche
Reunión:
Congreso; Third south american symposium in signal transduction and molecular medicine (SISTAM); 2015
Resumen:
p { margin-bottom: 0.25cm; direction: ltr; line-height: 120%; text-align: left; widows: 2; orphans: 2; }p.western { font-family: "Times New Roman",serif; font-size: 10pt; }p.cjk { font-family: "Times New Roman"; font-size: 10pt; }p.ctl { font-family: "Times New Roman"; font-size: 10pt; }a:link { color: rgb(0, 0, 255); }B3-adrenergicreceptor (B3AR)belongs to the superfamily of G protein-coupled receptors and whenactivated increases intracellular cAMP. It is mainly expressed inadipose tissues and bladder and has been postulated as targets forthe treatment of overactive bladder syndrome (OBS). Previous work inSK-N-MC cells, that endogenously express B3AR,showed that pretreatment with isoproterenol led to a significantdesensitization of the receptor. However, B3ARlacks potential sites for PKA or GRKs mediated phosphorylation, whichhave been demonstrated to be involved in B1ARand B2ARdesensitization.The aim of the presentwork was to evaluate the mechanism of B3ARdesensitization using HEK293T transfected cells. In this system,concentration-response assays to the specific B3ARligand BRL37344, significantly increased cAMP levels. Afterpretreatment with BRL37344, B3ARresponse was significantly reduced in a 40%. When different GRKs werecoexpressed, only GRK2 and 3, but not GRk5 or 6 increased receptordesensitization. Considering that GRKs possesses several structuraland functional domains, we cotransfected the cells with differentdominant negative mutants of the domains that can be involved inreceptor desensitization. When desensitization experiments wereperformed in presence of GRK2 dominant negative mutants, receptordesensitization was impeded only in presence of mutants of the RGSwhile expression of kinase inactive mutants had no effect. Presentresults indicate that B3ARresponse can be regulated by GRK2, where the RGS domain plays acrucial role.