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Biomedical subjects

D V Goeddel

Publications and source records attributed to D V Goeddel.

At least 19 recordsLinked to original sources

Defective lymphotoxin-beta receptor-induced NF-kappaB transcriptional activity in NIK-deficient mice.

The role of NF-kappaB-inducing kinase (NIK) in cytokine signaling remains controversial. To identify the physiologic functions of NIK, we disrupted the NIK locus by gene targeting. Although NIK-/- mice displayed abnormalities in both lymphoid tissue development and antibody responses, NIK-/- cells manifested normal NF-kappaB DNA binding activity when treated with a variety of cytokines, including tumor necrosis factor (TNF), interleukin-1 (IL-1), and lymphotoxin-beta (LTbeta). However, NIK was selectively required for gene transcription induced through ligation of LTbeta receptor but not TNF receptors. These results reveal that NIK regulates the transcriptional activity of NF-kappaB in a receptor-restricted manner.

Animals↗

T6BP, a TRAF6-interacting protein involved in IL-1 signaling.

We report the identification of a TRAF-interacting protein, T6BP, that specifically associates with TRAF6. This interaction occurs between the coiled-coil region of T6BP and the N-terminal ring finger and zinc finger domains of TRAF6. IL-1, but not tumor necrosis factor, induces TRAF6-T6BP complex formation in a ligand-dependent manner. Formation of the TRAF6-T6BP complex depends on the presence of the IL-1 receptor-associated kinase (IRAK). After IL-1 stimulation, TRAF6 can exist in two separate complexes, TRAF6-IRAK or TRAF6-T6BP, but IRAK is not present in TRAF6-T6BP complexes. T6BP does not seem to play a direct role in activation of IkappaB kinases or Jun N-terminal kinase.

Amino Acid Sequence↗

MIP-T3, a novel protein linking tumor necrosis factor receptor-associated factor 3 to the microtubule network.

In this study, we report the identification of a novel tumor necrosis factor receptor-associated factor 3 (TRAF3)-interacting protein designated MIP-T3. MIP-T3 is a 83-kDa protein with no significant homology to known mammalian proteins. MIP-T3 mRNA and TRAF3 mRNA are ubiquitously expressed, and TRAF3 is the only TRAF protein to interact with MIP-T3. The MIP-T3-TRAF3 interaction requires the coiled-coil TRAF-N domain of TRAF3. To our knowledge, this is the first case of a TRAF-binding protein that interacts with a single member of the TRAF family specifically through a TRAF-N coiled-coil domain. MIP-T3 binds to Taxol-stabilized microtubules and to tubulin in vitro, and MIP-T3 recruits TRAF3 to microtubules when both proteins are overexpressed in HeLa cells. In a 293 cell line stably expressing CD40, TRAF3 is released from the TRAF3.MIP-T3 complex and recruited to the CD40 receptor upon CD40 ligand stimulation. MIP-T3 may provide a novel mechanism in sequestering TRAF3 to the cytoskeletal network.

Amino Acid Sequence↗

Requirement for Casper (c-FLIP) in regulation of death receptor-induced apoptosis and embryonic development.

Casper (c-FLIP) associates with FADD and caspase-8 in signaling complexes downstream of death receptors like Fas. We generated Casper-deficient mice and cells and noted a duality in the physiological functions of this molecule. casper-/- embryos do not survive past day 10.5 of embryogenesis and exhibit impaired heart development. This phenotype is reminiscent of that reported for FADD-/- and caspase-8-/- embryos. However, unlike FADD-/- and caspase-8-/- cells, casper-/- embryonic fibroblasts are highly sensitive to FasL- or TNF-induced apoptosis and show rapid induction of caspase activities. NF-kappaB and JNK/SAPK activation is intact in TNF-stimulated casper-/- cells. These results suggest that Casper has two distinct roles: to cooperate with FADD and caspase-8 during embryonic development and to mediate cytoprotection against death factor-induced apoptosis.

Animals↗

TRAF6 deficiency results in osteopetrosis and defective interleukin-1, CD40, and LPS signaling.

Bone resorption and remodeling is an intricately controlled, physiological process that requires the function of osteoclasts. The processes governing both the differentiation and activation of osteoclasts involve signals induced by osteoprotegerin ligand (OPGL), a member of tumor necrosis factor (TNF) superfamily, and its cognate receptor RANK. The molecular mechanisms of the intracellular signal transduction remain to be elucidated. Here we report that mice deficient in TNF receptor-associated factor 6 (TRAF6) are osteopetrotic with defects in bone remodeling and tooth eruption due to impaired osteoclast function. Using in vitro assays, we demonstrate that TRAF6 is crucial not only in IL-1 and CD40 signaling but also, surprisingly, in LPS signaling. Furthermore, like TRAF2 and TRAF3, TRAF6 is essential for perinatal and postnatal survival. These findings establish unexpectedly diverse and critical roles for TRAF6 in perinatal and postnatal survival, bone metabolism, LPS, and cytokine signaling.

Animals↗

Prevention of constitutive TNF receptor 1 signaling by silencer of death domains.

Tumor necrosis factor receptor type 1 (TNF-R1) contains a cytoplasmic death domain that is required for the signaling of TNF activities such as apoptosis and nuclear factor kappa B (NF-kappaB) activation. Normally, these signals are generated only after TNF-induced receptor aggregation. However, TNF-R1 self-associates and signals independently of ligand when overexpressed. This apparent paradox may be explained by silencer of death domains (SODD), a widely expressed approximately 60-kilodalton protein that was found to be associated with the death domain of TNF-R1. TNF treatment released SODD from TNF-R1, permitting the recruitment of proteins such as TRADD and TRAF2 to the active TNF-R1 signaling complex. SODD also interacted with death receptor-3 (DR3), another member of the TNF receptor superfamily. Thus, SODD association may be representative of a general mechanism for preventing spontaneous signaling by death domain-containing receptors.

Adaptor Proteins, Signal Transducing↗

Embryonic lethality, liver degeneration, and impaired NF-kappa B activation in IKK-beta-deficient mice.

IkappaB kinase-alpha and -beta (IKK-alpha and IKK-beta), the catalytic subunits of the IKK complex, phosphorylate IkappaB proteins on specific serine residues, thus targeting IkappaB for degradation and activating the transcription factor NF-kappaB. To elucidate the in vivo function of IKK-beta, we generated IKK-beta-deficient mice. The homozygous mouse embryo dies at approximately 14.5 days of gestation due to liver degeneration and apoptosis. IKK-beta-deficient embryonic fibroblasts have both reduced basal NF-kappaB activity and impaired cytokine-induced NF-kappaB activation. Similarly, basal and cytokine-inducible kinase activities of the IKK complex are greatly reduced in IKK-beta-deficient cells. These results indicate that IKK-beta is crucial for liver development and regulation of NF-kappaB activity and that IKK-alpha can only partially compensate for the loss of IKK-beta.

Animals↗

NF-kappaB antiapoptosis: induction of TRAF1 and TRAF2 and c-IAP1 and c-IAP2 to suppress caspase-8 activation.

Tumor necrosis factor alpha (TNF-alpha) binding to the TNF receptor (TNFR) potentially initiates apoptosis and activates the transcription factor nuclear factor kappa B (NF-kappaB), which suppresses apoptosis by an unknown mechanism. The activation of NF-kappaB was found to block the activation of caspase-8. TRAF1 (TNFR-associated factor 1), TRAF2, and the inhibitor-of-apoptosis (IAP) proteins c-IAP1 and c-IAP2 were identified as gene targets of NF-kappaB transcriptional activity. In cells in which NF-kappaB was inactive, all of these proteins were required to fully suppress TNF-induced apoptosis, whereas c-IAP1 and c-IAP2 were sufficient to suppress etoposide-induced apoptosis. Thus, NF-kappaB activates a group of gene products that function cooperatively at the earliest checkpoint to suppress TNF-alpha-mediated apoptosis and that function more distally to suppress genotoxic agent-mediated apoptosis.

Animals↗

NF-kappaB-inducing kinase activates IKK-alpha by phosphorylation of Ser-176.

Activation of the transcription factor NF-kappaB by inflammatory cytokines involves the successive action of NF-kappaB-inducing kinase (NIK) and two IkappaB kinases, IKK-alpha and IKK-beta. Here we show that NIK preferentially phosphorylates IKK-alpha over IKK-beta, leading to the activation of IKK-alpha kinase activity. This phosphorylation of IKK-alpha occurs specifically on Ser-176 in the activation loop between kinase subdomains VII and VIII. A mutant form of IKK-alpha containing alanine at residue 176 cannot be phosphorylated or activated by NIK and acts as a dominant negative inhibitor of interleukin 1- and tumor necrosis factor-induced NF-kappaB activation. Conversely, a mutant form of IKK-alpha containing glutamic acid at residue 176 is constitutively active. Thus, the phosphorylation of IKK-alpha on Ser-176 by NIK may be required for cytokine-mediated NF-kappaB activation.

Amino Acid Sequence↗

FADD: essential for embryo development and signaling from some, but not all, inducers of apoptosis.

FADD (also known as Mort-1) is a signal transducer downstream of cell death receptor CD95 (also called Fas). CD95, tumor necrosis factor receptor type 1 (TNFR-1), and death receptor 3 (DR3) did not induce apoptosis in FADD-deficient embryonic fibroblasts, whereas DR4, oncogenes E1A and c-myc, and chemotherapeutic agent adriamycin did. Mice with a deletion in the FADD gene did not survive beyond day 11.5 of embryogenesis; these mice showed signs of cardiac failure and abdominal hemorrhage. Chimeric embryos showing a high contribution of FADD null mutant cells to the heart reproduce the phenotype of FADD-deficient mutants. Thus, not only death receptors, but also receptors that couple to developmental programs, may use FADD for signaling.

Adaptor Proteins, Signal Transducing↗

IkappaB kinase-beta: NF-kappaB activation and complex formation with IkappaB kinase-alpha and NIK.

Activation of the transcription factor nuclear factor kappa B (NF-kappaB) by inflammatory cytokines requires the successive action of NF-kappaB-inducing kinase (NIK) and IkappaB kinase-alpha (IKK-alpha). A widely expressed protein kinase was identified that is 52 percent identical to IKK-alpha. IkappaB kinase-beta (IKK-beta) activated NF-kappaB when overexpressed and phosphorylated serine residues 32 and 36 of IkappaB-alpha and serines 19 and 23 of IkappaB-beta. The activity of IKK-beta was stimulated by tumor necrosis factor and interleukin-1 treatment. IKK-alpha and IKK-beta formed heterodimers that interacted with NIK. Overexpression of a catalytically inactive form of IKK-beta blocked cytokine-induced NF-kappaB activation. Thus, an active IkappaB kinase complex may require three distinct protein kinases.

Amino Acid Sequence↗

Tumor necrosis factor (TNF)-mediated kinase cascades: bifurcation of nuclear factor-kappaB and c-jun N-terminal kinase (JNK/SAPK) pathways at TNF receptor-associated factor 2.

TNF-induced activation of the transcription factor NF-kappaB and the c-jun N-terminal kinase (JNK/SAPK) requires TNF receptor-associated factor 2 (TRAF2). The NF-kappaB-inducing kinase (NIK) associates with TRAF2 and mediates TNF activation of NF-kappaB. Herein we show that NIK interacts with additional members of the TRAF family and that this interaction requires the conserved "WKI" motif within the TRAF domain. We also investigated the role of NIK in JNK activation by TNF. Whereas overexpression of NIK potently induced NF-kappaB activation, it failed to stimulate JNK activation. A kinase-inactive mutant of NIK was a dominant negative inhibitor of NF-kappaB activation but did not suppress TNF- or TRAF2-induced JNK activation. Thus, TRAF2 is the bifurcation point of two kinase cascades leading to activation of NF-kappaB and JNK, respectively.

Calcium-Calmodulin-Dependent Protein Kinases↗

Identification and characterization of an IkappaB kinase.

Activation of the transcription factor NF-kappaB by tumor necrosis factor (TNF) and interleukin-1 (IL-1) requires the NF-kappaB-inducing kinase (NIK). In a yeast two-hybrid screen for NIK-interacting proteins, we have identified a protein kinase previously known as CHUK. Overexpression of CHUK activates a NF-kappaB-dependent reporter gene. A catalytically inactive mutant of CHUK is a dominant-negative inhibitor of TNF-, IL-1-, TRAF-, and NIK-induced NF-kappaB activation. CHUK associates with the NF-kappaB inhibitory protein, IkappaB-alpha, in mammalian cells. CHUK specifically phosphorylates IkappaB-alpha on both serine 32 and serine 36, modifications that are required for targeted degradation of IkappaB-alpha via the ubiquitin-proteasome pathway. This phosphorylation of IkappaB-alpha is greatly enhanced by NIK costimulation. Thus, CHUK is a NIK-activated IkappaB-alpha kinase that links TNF- and IL-1-induced kinase cascades to NF-kappaB activation.

Cloning, Molecular↗