Involvement of G protein-coupled receptor kinases and arrestins in desensitization to follicle-stimulating hormone action.
FSH rapidly desensitizes the FSH-receptor (FSH-R) upon binding. Very little information is available concerning the regulatory proteins involved in this process. In the present study, we investigated whether G protein-coupled receptor kinases (GRKs) and arrestins have a role in FSH-R desensitization, using a mouse Ltk 7/12 cell line stably overexpressing the rat FSH-R as a model. We found that these cells, which express GRK2, GRK3, GRK5, and GRK6 as well as beta-arrestins 1 and 2 as detected by RT-PCR and by Western blotting, were rapidly desensitized in the presence of FSH. Overexpression of GRKs and/or beta-arrestins in Ltk 7/12 cells allowed us to demonstrate 1) that GRK2, -3, -5, -6a, and -6b inhibit the FSH-R-mediated signaling (from 71% to 96% of maximal inhibition depending on the kinase, P < 0.001); 2) that beta-arrestins 1 or 2 also decrease the FSH action when overexpressed (80% of maximal inhibition, P < 0.01) whereas dominant negative beta-arrestin 2 [319-418] potentiates it 8-fold (P < 0.001); 3) that beta-arrestins and GRKs (except GRK6a) exert additive inhibition on FSH-induced response; and 4) that FSH-R desensitization depends upon the endogenous expression of GRKs, since there is potentiation of the FSH response (2- to 3-fold, P < 0.05) with antisenses cDNAs for GRK2, -5, and -6, but not GRK3. Our results show that the desensitization of the FSH-induced response involves the GRK/arrestin system.
Troispoux
C
C
INRA/CNRS URA 1291, Station de Physiologie de la Reproduction des Mammifères Domestiques, Nouzilly, France.
Guillou
F
F
Elalouf
J M
JM
Firsov
D
D
Iacovelli
L
L
De Blasi
A
A
Combarnous
Y
Y
Reiter
E
E
D000818:Animals; D019390:Arrestins / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D016373:DNA, Antisense / Q000494:pharmacology; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D019204:GTP-Binding Proteins / Q000378:metabolism; D015870:Gene Expression; D005786:Gene Expression Regulation / Q000187:drug effects; D017930:Genes, Reporter / Q000235:genetics; D008156:Luciferases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000502:physiology*; D011962:Receptors, FSH / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D014162:Transfection
D019390:Arrestins; D016373:DNA, Antisense; D011962:Receptors, FSH; D011993:Recombinant Fusion Proteins; D005640:Follicle Stimulating Hormone; D000242:Cyclic AMP; D008156:Luciferases; D020794:Receptor Protein-Tyrosine Kinases; D019204:GTP-Binding Proteins