Fig. 5.
FGF23 production by HEKF cells transfected with wild-type or mutant Gsα. FGF23-producing HEKF cells were transiently transfected with either wild-type (WT) or fibrous dysplasia-causing Gsα mutants (R201C or R201H) to assess for the effect of increased cAMP caused by these mutations on FGF23 processing. (A) Cells transfected with mutated Gsα constructs had significantly higher levels of cAMP. (B) Transfected cells produced very high levels of FGF23 with relatively higher levels of total (intact + C-terminal FGF23) in all transfected cells. (C) However, the relative levels of total FGF23 to intact (iFGF23) were not higher in the cells bearing the mutated Gsα constructs, nor were the levels of total FGF23 different between cells transfected with WT versus mutant Gsα constructs. (D) Regression analysis of the relationship between total FGF23 versus intact FGF23 revealed there were significantly higher levels of total FGF23 than intact FGF23, consistent with greater processing of intact FGF23 in HEKF cells overexpressing Gsα and cAMP.