Transient membrane recruitment of IRAK-1 in response to LPS and IL-1beta requires TNF R1.
The transcription factor NF-kappaB is an essential regulator of the innate immune response that functions as the first line of defense against infections. Activation of the innate immune response by bacterial lipopolysaccharide (LPS) triggers production of tumor necrosis factor-alpha (TNF-alpha) followed by interleukin-1 (IL-1). The IL-1 receptor associated kinase-1 (IRAK-1) is an integral component of the LPS, TNF-alpha, and IL-1 signaling pathways that regulate NF-kappaB. Thus we hypothesized that IRAK-1 coordinates cellular NF-kappaB responses to LPS, TNF-alpha, and IL-1. In contrast to TNF-alpha where IRAK-1 subcellular localization does not change, treatment with LPS or IL-1 leads to a loss in cytoplasmic IRAK-1 with a coordinate increase in plasma membrane associated modified IRAK-1. In fibroblasts lacking the type 1 TNF-alpha receptor (TNF R1), IRAK-1 turnover is altered and modification of IRAK-1 in the plasma membrane is decreased in response to LPS and IL-1, respectively. When NF-kappaB controlled gene expression is measured, fibroblasts lacking TNF R1 are hyperresponsive to LPS, whereas a more variable response to IL-1 is seen. Further analysis of the LPS response revealed that plasma membrane-associated IRAK-1 is found in Toll 4, IL-1, and TNF R1-containing complexes. The data presented herein suggest a model whereby the TNF R1-IRAK-1 interaction integrates the cellular response to LPS, TNF-alpha, and IL-1, culminating in a cell poised to activate TNF-alpha-dependent NF-kappaB controlled gene expression. In the absence of TNF R1-dependent events, exposure to LPS or IL-1 leads to hyperactivation of the inflammatory response.
Lockett
Angelia
A
Dept. of Biochemistry & Molecular Biology, Indiana Univ. School of Medicine, 635 Barnhill Dr., MS 4071, Indianapolis, IN 46202-5122, USA.
Goebl
Mark G
MG
Harrington
Maureen A
MA
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D020672:I-kappa B Proteins / Q000235:genetics / Q000378:metabolism; D053577:Interleukin-1 Receptor Accessory Protein / Q000378:metabolism; D053592:Interleukin-1 Receptor-Associated Kinases / Q000235:genetics / Q000378:metabolism*; D053583:Interleukin-1beta / Q000494:pharmacology*; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D007976:Leupeptins / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D018345:Mice, Knockout; D053594:Myeloid Differentiation Factor 88 / Q000378:metabolism; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D061988:Proteasome Inhibitors; D011485:Protein Binding / Q000187:drug effects; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000494:pharmacology; D054875:Ubiquitination / Q000187:drug effects
C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D020672:I-kappa B Proteins; C507767:Il1rap protein, mouse; D053577:Interleukin-1 Receptor Accessory Protein; D053583:Interleukin-1beta; D015850:Interleukin-6; D007976:Leupeptins; D008070:Lipopolysaccharides; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; C000606205:Nfkbia protein, mouse; D061988:Proteasome Inhibitors; D047888:Receptors, Tumor Necrosis Factor, Type I; C506236:Tnfrsf1a protein, mouse; D014409:Tumor Necrosis Factor-alpha; D000072000:NF-KappaB Inhibitor alpha; D053592:Interleukin-1 Receptor-Associated Kinases; C507769:Irak1 protein, mouse; C507774:Irak4 protein, mouse; D046988:Proteasome Endopeptidase Complex; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde