Fig. 2.

PTH₁R ligand bias in vitro. A. Multiaxial plot of PTH analog efficacy in cAMP, calcium and ERK1/2 assays performed using HEK293 cells overexpressing human PTH₁R. Estimated RA_i values for each ligand are plotted to represent the magnitude and direction of effect in each signaling response. Figure adapted from Appleton et al. (2013) Methods Enzymol 522: 229–262 [52]. B. Effects of hPTH(1–34) and [D-Trp¹²,Tyr³⁴]-bPTH(7–34) [bPTH(7–34)] on cAMP production (left) and ERK1/2 activation (right) in 10 day-old cultures of differentiating primary calvarial osteoblasts isolated from wild type (WT) and β-arrestin2−/− mice. Figure adapted from Gesty-Palmer et al. (2009) Science – Transl Med 1ra1 [33]. C. Effects of hPTH (1–34) and [D-Trp¹²,Tyr³⁴]-bPTH(7–34) on the survival and random migration of primary calvarial osteoblasts isolated from wild type and β-arrestin2−/− mice. Anti-apoptotic effects (left) were measured in 10 day-old differentiating osteoblast cultures subjected to serum-withdrawal or exposed to etoposide in the presence or absence of hPTH(1–34) or [D-Trp¹²,Tyr³⁴]-bPTH(7–34). Random cell migration (right) was measured by scratch assay performed on 3-day old confluent monolayers of primary preosteoblasts. Figure adapted from Gesty-Palmer et al. Mol Endocrinol 27:296–314 [55].