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. Author manuscript; available in PMC: 2018 Sep 1.
Published in final edited form as: J Bone Miner Res. 2017 Jun 26;32(9):1816–1828. doi: 10.1002/jbmr.3171

Figure 5.

Figure 5

Rap1b negatively regulates osteoblast differentiation through inhibition of MAPK signaling. (A) Immunoblotting of Rap1b and actin shows the knockdown efficiency mediated by siRNA in C3H10T1/2 cells during osteoblast differentiation. (B) Analysis of alkaline phosphatase activity reveals that the Rap1b knockdown enhances osteoblast differentiation (mean ± SEM, p < 0.01, n=3). (C) Immunoblot analysis examines the effect of overexpressing a myc tagged (MT) Rap1b on FGF signaling effectors, including Fgfr1, Ras, phosphorylated Raf (pRaf), phosphorylated Erk1/2 (pErk1/2), phosphorylated P38 (pP38), phosphorylated JNK (pJNK). The level of actin is analyzed as a loading control. (D) Alkaline phosphatase analysis revealed that enhanced osteoblast differentiation caused by the Rap1b knockdown can be alleviated by an inhibitor (10 μM U0126) for Erk1/2 activation (mean ± SEM, p < 0.01, n=3). Imagines are representatives of three independent experiments.