Dephosphorylation is the Mechanism of Fibroblast Growth Factor Inhibition of Guanylyl Cyclase-B

Abstract

AbstractActivating mutations in fibroblast growth factor receptor 3 (FGFR3) and inactivating mutations of guanylyl cyclase-B (GC-B, also called NPRB or NPR2) cause dwarfism. FGF exposure inhibits GC-B activity in a chondrocyte cell line, but the mechanism of the inactivation is not known. Here, we report that FGF exposure causes dephosphorylation of GC-B in rat chondrosarcoma cells, which correlates with a rapid, potent and reversible inhibition of C-type natriuretic peptide-dependent activation of GC-B. Cells expressing a phosphomimetic mutant of GC-B that cannot be inactivated by dephosphorylation because it contains glutamate substitutions for all known phosphorylation sites showed no decrease in GC-B activity in response to FGF. We conclude that FGF rapidly inactivates GC-B by a reversible dephosphorylation mechanism, which may contribute to the signaling network by which activated FGFR3 causes dwarfism.HighlightsGuanylyl Cyclase-B is expressed in rat chondrosarcoma cellsFGF2 induces a rapid, potent, and reversible inhibition of GC-BFGF2 treatment causes GC-B dephosphorylationFGF2 does not inhibit a dephosphorylation-resistant form of GC-BDephosphorylation is the mechanism of FGF2-dependent inhibition of GC-BAbbreviationscGMPcyclic guanosine monophosphateGCguanylyl cyclaseNPnatriuretic peptidePBSphosphate buffered salineWTwild type