TY - JOUR
T1 - Molecular Basis for the Unique Deubiquitinating Activity of the NF-κB Inhibitor A20
AU - Lin, Su Chang
AU - Chung, Jee Y.
AU - Lamothe, Betty
AU - Rajashankar, Kanagalaghatta
AU - Lu, Miao
AU - Lo, Yu Chih
AU - Lam, Amy Y.
AU - Darnay, Bryant G.
AU - Wu, Hao
N1 - Funding Information:
We thank Igor Kourinov at The Northeastern Collaborative Access Team of Advanced Photon Source for help with diffraction data collection and Jin Wu for the maintenance of X-ray and computer equipment. This work was supported by National Institutes of Health grants (RO1 AI045937 to H.W. and RO1 AR053540 to B.G.D.) and institutional startup funds to B.G.D. S.-C.L. and Y.-C.L. are postdoctoral fellows of the Cancer Research Institute, and M.L. is a postdoctoral fellow of the American Heart Association. This work is based upon research conducted at the Northeastern Collaborative Access Team beamlines of the Advanced Photon Source, supported by award RR-15301 from the National Center for Research Resources at the National Institute of Health. Use of the Advanced Photon Source is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
PY - 2008/2/15
Y1 - 2008/2/15
N2 - Nuclear factor κB (NF-κB) activation in tumor necrosis factor, interleukin-1, and Toll-like receptor pathways requires Lys63-linked nondegradative polyubiquitination. A20 is a specific feedback inhibitor of NF-κB activation in these pathways that possesses dual ubiquitin-editing functions. While the N-terminal domain of A20 is a deubiquitinating enzyme (DUB) for Lys63-linked polyubiquitinated signaling mediators such as TRAF6 and RIP, its C-terminal domain is a ubiquitin ligase (E3) for Lys48-linked degradative polyubiquitination of the same substrates. To elucidate the molecular basis for the DUB activity of A20, we determined its crystal structure and performed a series of biochemical and cell biological studies. The structure reveals the potential catalytic mechanism of A20, which may be significantly different from papain-like cysteine proteases. Ubiquitin can be docked onto a conserved A20 surface; this interaction exhibits charge complementarity and no steric clash. Surprisingly, A20 does not have specificity for Lys63-linked polyubiquitin chains. Instead, it effectively removes Lys63-linked polyubiquitin chains from TRAF6 without dissembling the chains themselves. Our studies suggest that A20 does not act as a general DUB but has the specificity for particular polyubiquitinated substrates to assure its fidelity in regulating NF-κB activation in the tumor necrosis factor, interleukin-1, and Toll-like receptor pathways.
AB - Nuclear factor κB (NF-κB) activation in tumor necrosis factor, interleukin-1, and Toll-like receptor pathways requires Lys63-linked nondegradative polyubiquitination. A20 is a specific feedback inhibitor of NF-κB activation in these pathways that possesses dual ubiquitin-editing functions. While the N-terminal domain of A20 is a deubiquitinating enzyme (DUB) for Lys63-linked polyubiquitinated signaling mediators such as TRAF6 and RIP, its C-terminal domain is a ubiquitin ligase (E3) for Lys48-linked degradative polyubiquitination of the same substrates. To elucidate the molecular basis for the DUB activity of A20, we determined its crystal structure and performed a series of biochemical and cell biological studies. The structure reveals the potential catalytic mechanism of A20, which may be significantly different from papain-like cysteine proteases. Ubiquitin can be docked onto a conserved A20 surface; this interaction exhibits charge complementarity and no steric clash. Surprisingly, A20 does not have specificity for Lys63-linked polyubiquitin chains. Instead, it effectively removes Lys63-linked polyubiquitin chains from TRAF6 without dissembling the chains themselves. Our studies suggest that A20 does not act as a general DUB but has the specificity for particular polyubiquitinated substrates to assure its fidelity in regulating NF-κB activation in the tumor necrosis factor, interleukin-1, and Toll-like receptor pathways.
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U2 - 10.1016/j.jmb.2007.11.092
DO - 10.1016/j.jmb.2007.11.092
M3 - Article
C2 - 18164316
AN - SCOPUS:38549146936
VL - 376
SP - 526
EP - 540
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
SN - 0022-2836
IS - 2
ER -