Activated FGFR3 increases HPV-31 E2 levels. HEK293TT cells were transfected with pCI or FLAG-FGFR3 K650E and FLAG-HPV-31 E1 or FLAG-HPV-31 E2 constructs. Forty-eight hours later, cells were lysed in 2% SDS, 150 mM NaCl, 10 mM Tris-HCl, pH 8.0. Immunoblotting was completed with FGFR3, M2 (FLAG), and β-actin antibodies.