Partially deglycosylated equine LH preferentially activates beta-arrestin-dependent signaling at the follicle-stimulating hormone receptor.
Deglycosylated FSH is known to trigger poor Galphas coupling while efficiently binding its receptor. In the present study, we tested the possibility that a deglycosylated equine LH (eLHdg) might be able to selectively activate beta-arrestin-dependent signaling. We compared native eLH to an eLH derivative [i.e. truncated eLHbeta (Delta121-149) combined with asparagine56-deglycosylated eLHalpha (eLHdg)] previously reported as an antagonist of cAMP accumulation at the FSH receptor (FSH-R). We confirmed that, when used in conjunction with FSH, eLHdg acted as an antagonist for cAMP accumulation in HEK-293 cells stably expressing the FSH-R. Furthermore, when used alone at concentrations up to 1 nM, eLHdg had no detectable agonistic activity on cAMP accumulation, protein kinase A activity or cAMP-responsive element-dependent transcriptional activity. At higher concentrations, however, a weak agonistic action was observed with eLHdg, whereas eLH led to robust responses whatever the concentration. Both eLH and eLHdg triggered receptor internalization and led to beta-arrestin recruitment. Both eLH and eLHdg triggered ERK and ribosomal protein (rp) S6 phosphorylation at 1 nM. The depletion of endogenous beta-arrestins had only a partial effect on eLH-induced ERK and rpS6 phosphorylation. In contrast, ERK and rpS6 phosphorylation was completely abolished at all time points in beta-arrestin-depleted cells. Together, these results show that eLHdg has the ability to preferentially activate beta-arrestin-dependent signaling at the FSH-R. This finding provides a new conceptual and experimental framework to revisit the physiological meaning of gonadotropin structural heterogeneity. Importantly, it also opens a field of possibilities for the development of selective modulators of gonadotropin receptors.
Wehbi
Vanessa
V
Unité Mixte de Recherche 6175, 37380 Nouzilly, France.
Tranchant
Thibaud
T
Durand
Guillaume
G
Musnier
Astrid
A
Decourtye
Jérémy
J
Piketty
Vincent
V
Butnev
Vladimir Y
VY
Bousfield
George R
GR
Crépieux
Pascale
P
Maurel
Marie-Christine
MC
Reiter
Eric
E
D000818:Animals; D019390:Arrestins / Q000378:metabolism*; D015153:Blotting, Western; D002417:Cattle; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006736:Horses; D006801:Humans; D047468:Immunoprecipitation; D007986:Luteinizing Hormone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D051379:Mice; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding; D021381:Protein Transport / Q000187:drug effects; D034741:RNA, Small Interfering; D011962:Receptors, FSH / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D038601:Ribosomal Protein S6 / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D013552:Swine; D000071557:beta-Arrestins
D019390:Arrestins; D034741:RNA, Small Interfering; D011962:Receptors, FSH; D038601:Ribosomal Protein S6; D000071557:beta-Arrestins; C030405:luteinizing hormone, deglycosylated; D007986:Luteinizing Hormone; D017868:Cyclic AMP-Dependent Protein Kinases