Inhibition of dynamin- or β-arrestin-mediated FSH-R internalization does not impair FSH-induced ERK phosphorylation. A: Immunodetection of P-ERK, of endogenous β-arrestins and of β-arrestin (319–418) as indicated, following 4, 8 and 12 min of FSH stimulation. n.s. = non specific. MWM = molecular weight marker (kDa). B: Quantification of P-ERK in response to 8 min of FSH stimulation (n = 3 independent experiments).