Hsp70 inhibits lipopolysaccharide-induced NF-kappaB activation by interacting with TRAF6 and inhibiting its ubiquitination |
| |
Authors: | Chen Huaqun Wu Yifan Zhang Yiqing Jin Lina Luo Lan Xue Bin Lu Chen Zhang Xiran Yin Zhimin |
| |
Affiliation: | Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 122 Ninghai Road, Nanjing 210097, Jiangsu Province, PR China. |
| |
Abstract: | Inducible heat shock protein 70 (Hsp70) is one of the most important HSPs for maintenance of cell integrity during normal cellular growth as well as pathophysiological conditions. Tumor necrosis factor receptor-associated factor 6 (TRAF6) is a crucial signaling transducer that regulates a diverse array of physiological and pathological processes and is essential for activating NF-kappaB signaling pathway in response to bacterial lipopolysaccharide (LPS). Here we report a novel mechanism of Hsp70 for preventing LPS-induced NF-kappaB activation in RAW264.7 macrophage-like cells. Our results show that Hsp70 can associate with TRAF6 physically in the TRAF-C domain and prevent TRAF6 ubiquitination. The stimulation of LPS dissociates the binding of Hsp70 and TRAF6 in a time-dependent manner. Hsp70 inhibits LPS-induced NF-kappaB signaling cascade activation in heat-shock treated as well as Hsp70 stable transfected RAW264.7 cells and subsequently decreases iNOS and COX-2 expression. Two Hsp70 mutants, Hsp70DeltaC(1-428aa) with N-terminal ATPase domain and Hsp70C(428-642aa) with C-terminal domain, lack the ability to influence TRAF6 ubiquitination and TRAF6-triggered NF-kappaB activation. Taken together, these findings indicate that Hsp70 inhibits LPS-induced NF-kappaB activation by binding TRAF6 and preventing its ubiquitination, and results in inhibition of inflammatory mediator production, which provides a new insight for analyzing the effects of Hsp70 on LPS-triggered inflammatory signal transduction pathways. |
| |
Keywords: | Hsp70, heat shock protein 70 TRAF6, tumor necrosis factor receptor-associated factor 6 LPS, lipopolysaccharide NF-κB, nuclear factor-κB IκBα, inhibitor of NF-κB α IKK, IκB kinase MAPKs, mitogen-activated protein kinases JNK, c-Jun N-terminal kinase iNOS, inducible nitric oxide synthase COX-2, cyclooxygenase-2 |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|