TY - JOUR
T1 - Thioredoxin-1 actively maintains the pseudokinase MLKL in a reduced state to suppress disulfide bond-dependent MLKL polymer formation and necroptosis
AU - Reynoso, Eduardo
AU - Liu, Hua
AU - Li, Lin
AU - Yuan, Anthony L.
AU - Chen, She
AU - Wang, Zhigao
N1 - Publisher Copyright:
© 2017 by The American Society for Biochemistry and Molecular Biology, Inc.
PY - 2017/10/20
Y1 - 2017/10/20
N2 - Necroptosis is an immunogenic cell death program that is associated with a host of human diseases, including inflammation, infections, and cancer. Receptor-interacting protein kinase 3 (RIPK3) and its substrate mixed lineage kinase domainlike protein (MLKL) are required for necroptosis activation. Specifically, RIPK3-dependent MLKL phosphorylation promotes the assembly of disulfide bond-dependent MLKL polymers that drive the execution of necroptosis. However, how MLKL disulfide bond formation is regulated is not clear. In this study we discovered that the MLKL-modifying compound necrosulfonamide cross-links cysteine 86 of human MLKL to cysteine 32 of the thiol oxidoreductase thioredoxin-1 (Trx1). Recombinant Trx1 preferentially binds to monomeric MLKL and blocks MLKL disulfide bond formation and polymerization in vitro. Inhibition of MLKL polymer formation requires the reducing activity of Trx1. Importantly, shRNA-mediated knockdown of Trx1 promotes MLKL polymerization and sensitizes cells to necroptosis. Furthermore, pharmacological inhibition of Trx1 with compound PX-12 induces necroptosis in multiple cancer cell lines. Altogether, these findings demonstrate that Trx1 is a critical regulator of necroptosis that suppresses cell death by maintaining MLKL in a reduced inactive state. Our results further suggest new directions for targeted cancer therapy in which thioredoxin inhibitors like PX-12 could potentially be used to specifically target cancers expressing high levels of MLKL or MLKL short isoforms.
AB - Necroptosis is an immunogenic cell death program that is associated with a host of human diseases, including inflammation, infections, and cancer. Receptor-interacting protein kinase 3 (RIPK3) and its substrate mixed lineage kinase domainlike protein (MLKL) are required for necroptosis activation. Specifically, RIPK3-dependent MLKL phosphorylation promotes the assembly of disulfide bond-dependent MLKL polymers that drive the execution of necroptosis. However, how MLKL disulfide bond formation is regulated is not clear. In this study we discovered that the MLKL-modifying compound necrosulfonamide cross-links cysteine 86 of human MLKL to cysteine 32 of the thiol oxidoreductase thioredoxin-1 (Trx1). Recombinant Trx1 preferentially binds to monomeric MLKL and blocks MLKL disulfide bond formation and polymerization in vitro. Inhibition of MLKL polymer formation requires the reducing activity of Trx1. Importantly, shRNA-mediated knockdown of Trx1 promotes MLKL polymerization and sensitizes cells to necroptosis. Furthermore, pharmacological inhibition of Trx1 with compound PX-12 induces necroptosis in multiple cancer cell lines. Altogether, these findings demonstrate that Trx1 is a critical regulator of necroptosis that suppresses cell death by maintaining MLKL in a reduced inactive state. Our results further suggest new directions for targeted cancer therapy in which thioredoxin inhibitors like PX-12 could potentially be used to specifically target cancers expressing high levels of MLKL or MLKL short isoforms.
UR - http://www.scopus.com/inward/record.url?scp=85032029609&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85032029609&partnerID=8YFLogxK
U2 - 10.1074/jbc.M117.799353
DO - 10.1074/jbc.M117.799353
M3 - Article
C2 - 28878015
AN - SCOPUS:85032029609
SN - 0021-9258
VL - 292
SP - 17514
EP - 17524
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 42
ER -