Pellino 2 is critical for Toll-like receptor/interleukin-1 receptor (TLR/IL-1R)-mediated post-transcriptional control.
Interleukin 1 receptor-associated kinase 1(IRAK1), a key molecule in TLR/IL-1R-mediated signaling, is phosphorylated, ubiquitinated, and degraded upon ligand stimulation. We and others have recently identified Pellino proteins as novel RING E3 ubiquitin ligases involved in IRAK1 polyubiquitination and degradation. However, it remains unclear how each Pellino member distinctly regulates TLR/IL-1R signaling by modulating IRAK1 ubiquitination. In this study we examined the role of Pellino 2 in IL-1- and LPS-mediated signaling and gene expression by knocking down Pellino 2 in human 293-IL-1R cells and primary bone marrow macrophages. Pellino 2 (but not Pellino 1) knockdown abolished IL-1- and LPS-induced Lys-63-linked IRAK1 ubiquitination with reduced Lys-48-linked IRAK1 ubiquitination. Furthermore, Pellino 2 is required for TAK1-dependent NFκB activation. However, because of the retained TAK1-independent NFκB activation, the levels of IL-1- and LPS-induced NFκB activation were not substantially affected in Pellino 2 knockdown 293-IL-1R cells and primary macrophages, respectively. On the other hand, Pellino 2 knockdown reduced the IL-1- and LPS-induced inflammatory gene expression at late time points, which was accompanied by increased decay rates of the mRNAs of the inflammatory genes. Importantly, IL-1- and LPS-mediated JNK and ERK activation were substantially attenuated in Pellino 2 knock-down cells, implicating MAPK activation in TLR/IL-1R-induced mRNA stabilization. Taken together, this study demonstrated that Pellino 2 plays a critical role for TLR/IL-1R-mediated post-transcriptional control.
Department of Immunology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Tae Whan
TW
Kim
Minjia
M
Yu
Hao
H
Zhou
Wei
W
Cui
Jianan
J
Wang
Paul
P
DiCorleto
Paul
P
Fox
Hui
H
Xiao
Xiaoxia
X
Li
D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D055785:Gene Knockdown Techniques; D057809:HEK293 Cells; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D020871:RNA Stability / Q000187:drug effects / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017472:Receptors, Interleukin-1 / Q000235:genetics / Q000378:metabolism*; D051193:Toll-Like Receptors / Q000235:genetics / Q000378:metabolism*; D000099151:MAP Kinase Kinase Kinase 7
D007375:Interleukin-1; D008070:Lipopolysaccharides; D020930:MAP Kinase Kinase Kinases; D016328:NF-kappa B; D009687:Nuclear Proteins; D012333:RNA, Messenger; D017472:Receptors, Interleukin-1; D051193:Toll-Like Receptors; D000099151:MAP Kinase Kinase Kinase 7; C485961:Peli2 protein, mouse