Fig. 2.

GHRH-induced β-arrestin recruitment and pERK1/2 signaling mediated by GHRHR and SV1. (A and B) β-arrestin recruitment by GHRHR and SV1. Comparison of SV1 with full-length or truncated GHRHR that lacks the entire ECD or the first 89 residues (A). Comparison of SV1 and various N terminus truncated GHRHRs. The assay was initiated by 250 μM GHRH (B). The response was calculated as AUC across the full kinetic trace. *P < 0.01 and **P < 0.001 compared with GHRHR; Δ, truncation. (C and D) Time-course of ERK1/2 activation. The assay was initiated by 1 μM GHRH and inhibition was achieved by 4 μM MIA-602 in HEK293T cells expressing GHRHR or SV1 (C) and prostate cancer cell lines (D). Data shown are means ± SEM of at least four independent experiments (n = 4 to 6) performed in duplicate. *P < 0.05; **P < 0.01.