Yu Y, Ge N, Xie M, Sun W, Burlingame S, Pass AK et al.. Phosphorylation of Thr-178 and Thr- 184 in the TAK1 T-loop is required for interleukin (IL)-1-mediated optimal NFkappaB and AP-1 activation as well as IL-6 gene expression. J Biol Chem 283: 24497-24505
Texas Children's Cancer Center, Department of Pediatrics, Center for Cardiovascular Development, Department of Medicine, and Michael E. DeBakey Department of Surgery, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030.
TAK1 (transforming growth factor-beta-activated kinase 1), a mitogen-activated protein kinase kinase kinase, is activated by various cytokines, including interleukin-1 (IL-1). However, the precise regulation for TAK1 activation at the molecular level is still not fully understood. Here we report that dual phosphorylation of Thr-178 and Thr-184 residues within the kinase activation loop of TAK1 is essential for TAK1-mediated NFkappaB and AP-1 activation. Once co-overexpressed with TAB1, TAK1 mutant with alanine substitution of these two residues fails to activate IKKbeta-mediated NFkappaB and JNK-mediated AP-1, whereas TAK1 mutant with replacement of these two sites with acidic residues acts like the TAK1 wild type. Consistently, TAK1 mutant with alanine substitution of these two residues severely inhibits IL-1-induced NFkappaB and AP-1 activities, whereas TAK1 mutant with replacement of these two sites with acidic residues slightly enhances IL-1-induced NFkappaB and AP-1 activities compared with the TAK1 wild-type. IL-1 induces the phosphorylation of endogenous TAK1 at Thr-178 and Thr-184. Reconstitution of TAK1-deficient mouse embryo fibroblast cells with wild-type TAK1 or a TAK1 mutant containing threonine 178 and 184 to alanine mutations revealed the importance of these two sites in IL-1-mediated IKK-NFkappaB and JNK-AP-1 activation as well as IL-1-induced IL-6 gene expression. Our finding is the first report that substitution of key serine/threonine residues with acidic residues mimics the phosphorylated state of TAK1 and renders TAK1 active during its induced activation.
"Ras is a small GTP-binding protein that induces activation of downstream Raf (a MAP3K), which translocates from the membrane to the cytosol to activate MEK1 (MAP2K1) and ERK1/2. The pathway can be activated by mitogenic stimuli growth factors like EGF and PDGF, insulin, or cytokines like interleukin-1b (IL-1b) (Wan, Chi, Xie, Schneider, & Flavell, 2006; Yu et al., 2008) and TGF-b (Ieda et al., 2009; Matsumoto-Ida et al., 2006). ERK1/2 can be activated via tyrosine kinase receptors and GPCRs and plays a significant role in cardiac "
[Show abstract][Hide abstract] ABSTRACT: Heart failure is one of the paramount global causes of morbidity and mortality. Despite this pandemic need, the available clinical counter-measures have not altered substantially in recent decades, most notably in the context of pharmacological interventions. Cell death plays a causal role in heart failure, and its inhibition poses a promising approach that has not been thoroughly explored. In previous approaches to target discovery, clinical failures have reflected a deficiency in mechanistic understanding, and in some instances, failure to systematically translate laboratory findings toward the clinic. Here, we review diverse mouse models of heart failure, with an emphasis on those that identify potential targets for pharmacological inhibition of cell death, and on how their translation into effective therapies might be improved in the future.
Current Topics in Developmental Biology 06/2014; 109:171-247. DOI:10.1016/B978-0-12-397920-9.00002-0 · 4.68 Impact Factor
"Upon cytokine stimulation, TAK1 undergoes auto-phosphorylation as a result of association with TAB2/3-polyubiquitin chains  or TAB1-dependent oligomerization [30,38]. Phosphorylation occurs at four conserved serine and threonine residues within TAK1 activation loop, including Thr-178, Thr-184, Thr-187, and Ser-192 [28,30,31,39,40], among which Thr-187 phosphorylation has a major role in regulating TAK1 activity [30,31]. TNFα, IL-1β, and TGFβ cause K63-linked polyubiquitination of TAK1 by TRAF2 or TRAF6 [41,42]. "
[Show abstract][Hide abstract] ABSTRACT: Background
The Vpr protein of human immunodeficiency virus type 1 (HIV-1) plays an important role in viral replication. It has been reported that Vpr stimulates the nuclear factor-κB (NF-κB) and activator protein 1 (AP-1) signaling pathways, and thereby regulates viral and host cell gene expression. However, the molecular mechanism behind this function of Vpr is not fully understood.
Here, we have identified transforming growth factor-β-activated kinase 1 (TAK1) as the important upstream signaling molecule that Vpr associates with in order to activate NF-κB and AP-1 signaling. HIV-1 virion-associated Vpr is able to stimulate phosphorylation of TAK1. This activity of Vpr depends on its association with TAK1, since the S79A Vpr mutant lost interaction with TAK1 and was unable to activate TAK1. This association allows Vpr to promote the interaction of TAB3 with TAK1 and increase the polyubiquitination of TAK1, which renders TAK1 phosphorylation. In further support of the key role of TAK1 in this function of Vpr, knockdown of endogenous TAK1 significantly attenuated the ability of Vpr to activate NF-κB and AP-1 as well as the ability to stimulate HIV-1 LTR promoter.
HIV-1 Vpr enhances the phosphorylation and polyubiquitination of TAK1, and as a result, activates NF-κB and AP-1 signaling pathways and stimulates HIV-1 LTR promoter.
"In support of this notion it has previously been reported that calcium channel blockers administered prior to the same protocol used in the present investigation resulted in reduced skeletal muscle damage, suggesting a role for calcium-induced cellular damage . Importantly, contraction-induced calcineurin-NFAT, IL-1, AP-1, NFκB, and nitric oxide signaling have been shown to induce IL-6 gene expression in muscle ,  (for an extensive review see ref. ), suggesting a potential role for calcium-induced IL-6 expression. Muscle produced IL-6 can act in an autocrine fashion, binding to the IL-6Rα on the sarcolemma, initiating the activation of the JAK/STAT3 signaling pathway , , . "
[Show abstract][Hide abstract] ABSTRACT: The regulation of muscle stem cells in humans in response to muscle injury remains largely undefined. Recently, interleukin-6 (IL-6) has been implicated in muscle stem cell (satellite cell)-mediated muscle hypertrophy in animals; however, the role of IL-6 in the satellite cell (SC) response following muscle-lengthening contractions in humans has not been studied.
Eight subjects (age 22+/-1 y; 79+/-8 kg) performed 300 maximal unilateral lengthening contractions (3.14 rad.s(-1)) of the knee extensors. Blood and muscle samples were collected before and at 4, 24, 72, and 120 hours post intervention. IL-6, IL-6 receptor, IL-6R(alpha), cyclin D1, suppressor of cytokine signling-3 (SOCS3) mRNA were measured using quantitative RT-PCR and serum IL-6 protein was measured using an ELISA kit. JAK2 and STAT3 phosphorylated and total protein was measured using western blotting techniques. Immunohistochemical analysis of muscle cross-sections was performed for the quantification of SCs (Pax7(+) cells) as well as the expression of phosphorylated STAT3, IL-6, IL-6R(alpha), and PCNA across all time-points. The SC response, as defined by an amplification of Pax7(+) cells, was rapid, increasing by 24 h and peaking 72 h following the intervention. Muscle IL-6 mRNA increased following the intervention, which correlated strongly (R(2) = 0.89, p<0.002) with an increase in serum IL-6 concentration. SC IL-6R(alpha) protein was expressed on the fiber, but was also localized to the SC, and IL-6(+) SC increased rapidly following muscle-lengthening contractions and returned to basal levels by 72 h post-intervention, demonstrating an acute temporal expression of IL-6 with SC. Phosphorylated STAT3 was evident in SCs 4 h after lengthening contraction, and the downstream genes, cyclin D1 and SOCS3 were significantly elevated 24 hours after the intervention.
The increased expression of STAT3 responsive genes and expression of IL-6 within SCs demonstrate that IL-6/STAT3 signaling occurred in SCs, correlating with an increase in SC proliferation, evidenced by increased Pax7(+)/PCNA(+) cell number in the early stages of the time-course. Collectively, these data illustrate that IL-6 is an important signaling molecule associated with the SC response to acute muscle-lengthening contractions in humans.
PLoS ONE 06/2009; 4(6):e6027. DOI:10.1371/journal.pone.0006027 · 3.23 Impact Factor
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