01680nas a2200265   4500000000100000008004100001653001700042653000800059653001600067653001000083653002400093653001000117653001200127653000800139100001000147700001200157700001000169700000900179700001000188700001000198700001000208245011400218520106800332022001401400       2018                            d10aanti-leprosy10aBLI10aClofazimine10aDrugs10aERK phosphorylation10ahRKIP10aleprosy10aNMR1 aGuo C1 aChang T1 aSun T1 aWu Z1 aDai Y1 aYao H1 aLin D00aAnti-leprosy drug Clofazimine binds to human Raf1 kinase inhibitory protein and enhances ERK phosphorylation.3 a<p>Human Raf1 kinase inhibitory protein (hRKIP) is an important modulator of the Ras/Raf1/MEK/ERK signaling pathway. Here, we demonstrated that anti-leprosy drug Clofazimine can bind to hRKIP with a significantly stronger affinity than the endogenous substrate phosphatidylethanolamine (PE) by using Biolayer interference technology. Moreover, we identified that residues P74, S75, K80, P111, P112, V177, and P178 play crucial roles in the binding of hRKIP to Clofazimine by using a combination of Nuclear Magnetic Resonance spectroscopy and molecular docking approach. These residues are located at the conserved ligand-binding pocket of hRKIP. Furthermore, we found that 3.2 μM Clofazimine could significantly increase the ERK phosphorylation level by about 37%. Our results indicate that Clofazimine can enhance Ras/Raf1/MEK/ERK signaling transduction pathway via binding to hRKIP. This work provides valuable hints for exploiting Clofazimine as a potential lead compound to efficiently treat the diseases related to RKIP or the Ras/Raf/MEK/ERK pathway.</p>
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