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Transforming growth factor-β (TGF-β) activated kinase 1 (TAK1), also named mitogen-activated protein kinase 7 (MAPK7), forms a pivotal signaling complex with TAK1-binding proteins (TAB1, TAB2, and TAB3), orchestrating critical biological processes, including immune responses, cell growth, apoptosis, and stress responses. Activation of TAK1 by stimuli, such as tumor necrosis factor α (TNFα), interleukin-1β (IL-1β), and Toll-like receptors (TLRs), underscores its central role in cellular signaling. Given the critical role of the TAK1-binding protein (TAK1–TAB) complex in cellular signaling and its impact on various biological processes, this review seeks to understand how ubiquitination thoroughly regulates the TAK1–TAB complex. This understanding is vital for developing targeted therapies for diseases where this signaling pathway is dysregulated. The exploration is significant as it unveils new insights into the activity, stability, and assembly of the complex, underscoring its therapeutic potential in disease modulation.

Transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1), TAK1-binding protein 1 (TAB1) and TAB2 are components of the mitogen-activated protein kinase (MAPK) pathway. In this study, TAK1, TAB1 and TAB2 were characterized from golden pompano (Trachinotus ovatus), a marine fish of great economic value, and named as trTAK1, trTAB1 and trTAB2, respectively. The lengths of the cDNA sequences of the three genes were 2429 bp, 2068 bp and 4229 bp and encoded 575, 506 and 759 amino acids, respectively. The trTAK1, trTAB1 and trTAB2 genes shared high sequence identities and were well clustered with their counterparts from other fish species. Real-time qPCR analysis showed that the three genes were constitutively expressed in all the selected tissues of healthy pompano, and the expression levels of the three genes were significantly up-regulated in head kidney and spleen following Vibrio alginolyticus, lipolysaccharide (LPS) and polyinosinic polycytidylic acid (poly I:C) challenge, indicating their roles in the immune response against pathogens in golden pompano. Our results provide a basis for further study of the functions of these genes in golden pompano. [ABSTRACT FROM AUTHOR]

Summary: Selective autophagy is a catabolic route that turns over specific cellular material for degradation by lysosomes, and whose role in the regulation of innate immunity is largely unexplored. Here, we show that the apical kinase of the Drosophila immune deficiency (IMD) pathway Tak1, as well as its co-activator Tab2, are both selective autophagy substrates that interact with the autophagy protein Atg8a. We also present a role for the Atg8a-interacting protein Sh3px1 in the downregulation of the IMD pathway, by facilitating targeting of the Tak1/Tab2 complex to the autophagy platform through its interaction with Tab2. Our findings show the Tak1/Tab2/Sh3px1 interactions with Atg8a mediate the removal of the Tak1/Tab2 signaling complex by selective autophagy. This in turn prevents constitutive activation of the IMD pathway in Drosophila. This study provides mechanistic insight on the regulation of innate immune responses by selective autophagy.

Transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1), TAK1-binding protein 1 (TAB1) and TAB2 are components of the mitogen-activated protein kinase (MAPK) pathway. In this study, TAK1, TAB1 and TAB2 were characterized from golden pompano (Trachinotus ovatus), a marine fish of great economic value, and named as trTAK1, trTAB1 and trTAB2, respectively. The lengths of the cDNA sequences of the three genes were 2429 bp, 2068 bp and 4229 bp and encoded 575, 506 and 759 amino acids, respectively. The trTAK1, trTAB1 and trTAB2 genes shared high sequence identities and were well clustered with their counterparts from other fish species. Real-time qPCR analysis showed that the three genes were constitutively expressed in all the selected tissues of healthy pompano, and the expression levels of the three genes were significantly up-regulated in head kidney and spleen following Vibrio alginolyticus, lipolysaccharide (LPS) and polyinosinic polycytidylic acid (poly I:C) challenge, indicating their roles in the immune response against pathogens in golden pompano. Our results provide a basis for further study of the functions of these genes in golden pompano.

Deletions encompassing TAK1-binding protein 2 ( TAB2) associated with isolated and syndromic congenital heart defects. Rare missense variants are found in patients with a similar phenotype as well as in a single individual with frontometaphyseal dysplasia. We describe a family and an additional sporadic patient with polyvalvular heart disease, generalized joint hypermobility and related musculoskeletal complications, soft, velvety and hyperextensible skin, short limbs, hearing impairment, and facial dysmorphism. In the first family, whole-exome sequencing (WES) disclosed the novel TAB2 c.1398dup (p. Thr467Tyrfs*6) variant that eliminates the C-terminal zinc finger domain essential for activation of TAK1 ( TGFβ-activated kinase 1)-dependent signaling pathways. The sporadic case carryed a ~2 Mb de novo deletion including 28 genes also comprising TAB2. This study reveal an association between TAB2 mutations and a phenotype resembling Ehlers-Danlos syndrome with severe polyvalvular heart disease and subtle facial dysmorphism. Our findings support the existence of a wider spectrum of clinical phenotypes associated with TAB2 perturbations and emphasize the role of TAK1 signaling network in human development. [ABSTRACT FROM AUTHOR]

Frontometaphyseal dysplasia (FMD) is caused by gain-of-function mutations in the X-linked gene FLNA in approximately 50% of patients. Recently we characterized an autosomal dominant form of FMD (AD-FMD) caused by mutations in MAP3K7, which accounts for the condition in the majority of patients who lack a FLNA mutation. We previously also described a patient with a de novo variant in TAB2, which we hypothesized was causative of another form of AD-FMD. In this study, a cohort of 20 individuals with AD-FMD is clinically evaluated. This cohort consists of 15 individuals with the recently described, recurrent mutation (c.1454C>T) in MAP3K7, as well as three individuals with missense mutations that result in substitutions in the N-terminal kinase domain of TGFβ-activated kinase 1 (TAK1), encoded by MAP3K7. Additionally, two individuals have missense variants in the gene TAB2, which encodes a protein with a close functional relationship to TAK1, TAK1-associated binding protein 2 (TAB2). Although the X-linked and autosomal dominant forms of FMD are very similar, there are distinctions to be made between the two conditions. Individuals with AD-FMD have characteristic facial features, and are more likely to be deaf, have scoliosis and cervical fusions, and have a cleft palate. Furthermore, there are features only found in AD-FMD in our review of the literature including valgus deformity of the feet and predisposition to keloid scarring. Finally, intellectual disability is present in a small number of subjects with AD-FMD but has not been described in association with X-linked FMD. [ABSTRACT FROM AUTHOR]

Transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1) is a member of the mitogen-activated protein kinase kinase kinase (MAPKKK) family that is activated by growth factors and cytokines such as TGF-β, IL-1β, and TNF-α, and mediates a wide range of biological processes through activation of the nuclear factor-κB (NF-κB) and the mitogen-activated protein (MAP) kinase signaling pathways. It is well established that activation status of TAK1 is tightly regulated by forming a complex with its binding partners, TAK1-binding proteins (TAB1, TAB2, and TAB3). Interestingly, recent evidence indicates the importance of post-translational modifications (PTMs) of TAK1 and TABs in the regulation of TAK1 activation. To date, a number of PTMs of TAK1 and TABs have been revealed, and these PTMs appear to fine-tune and coordinate TAK1 activities depending on the cellular context. This review therefore focuses on recent advances in the understanding of the PTMs of the TAK1-TAB complex. [ABSTRACT FROM AUTHOR]

LvTAK1, a member of transforming growth factor β-activated kinase 1 (TAK1) families, has been identified from Litopenaeus vannamei in this study. The full length of LvTAK1 is 2670 bp, including a 2277 bp open reading frame (ORF) that encoded a putative protein of 758 amino acids with a calculated molecular weight of ∼83.4 kDa LvTAK1 expression was most abundant in muscles and was up-regulated in gills after LPS, Vibrio parahaemolyticus, Staphhylococcu saureus, Poly (I:C) and WSSV challenge. Both in vivo and in vitro experiments indicated that LvTAK1 could activate the expression of several antimicrobial peptide genes (AMPs). In addition, the dsRNA-mediated knockdown of LvTAK1 enhanced the susceptibility of shrimps to Vibrio parahaemolyticus, a kind of Gram-negative bacteria. These results suggested LvTAK1 played important roles in anti-bacterial infection. CoIP and subcellular localization assay demonstrated that LvTAK1 could interact with its binding protein LvTAB2, a key component of IMD pathway. Moreover, over-expression of LvTAK1 in Drosophila S2 cell could strongly induce the promoter activity of Diptericin (Dpt), a typical AMP which is used to read out of the activation of IMD pathway. These findings suggested that LvTAK1 could function as a component of IMD pathway. Interestingly, with the over-expression of LvTAK1 in S2 cell, the promoter activity of Metchnikowin (Mtk), a main target gene of Toll/Dif pathway, was up-regulated over 30 times, suggesting that LvTAK1 may also take part in signal transduction of the Toll pathway. In conclusion, we provided some evidences that the involvement of LvTAK1 in the regulation of both Toll and IMD pathways, as well as innate immune against bacterial infection in shrimp. [ABSTRACT FROM AUTHOR]

Phosphoinositide-dependent protein kinase 1 (PDK1) plays a key role in the phosphoinositide 3-kinase (PI3K)–PDK1–Akt pathway that induces cell survival and cardiovascular protections through anti-apoptosis, vasodilation, anti-inflammation, and anti-oxidative stress activities. Although several reports have proposed the negative role of PDK1 in Toll-like receptor 4 (TLR4) signaling, the molecular mechanism is still unknown. Here we show that PDK1 inhibits tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) ubiquitination by interrupting the complex between transforming growth factor beta-activated kinase 1 (TAK1) and TAK1 binding protein 2 (TAB2), which negatively regulates TAK1 activity. The overexpression of PDK1 in 293/TLR4 cells resulted in suppressions of nuclear factor kappa B (NF-κB) activation and production of proinflammatory cytokines including interleukin (IL)-6 and TNF-α in response to lipopolysaccharide stimulation. Conversely, THP-1 human monocytes transiently cultured in low glucose medium displayed down-regulated PDK1 expression, and significantly enhanced TLR4-mediated signaling for the activation of NF-κB, demonstrating a negative role of PDK1. Biochemical studies revealed that PDK1 significantly interacted with TAK1, resulting in the inhibition of the association of TAB2 with TAK1, which led to the attenuation of TRAF6 ubiquitination. Moreover, PDK1-knockdown THP-1 cells displayed enhancement of downstream signals, activation of NF-κB, and increased production of pro-inflammatory cytokines IL-6, IL-1β, and TNF-α, which potentially led to the up-regulation of NF-κB-dependent genes in response to TLR4 stimulation. Collectively, the results demonstrate that PDK1 inhibits the formation of the TAK1–TAB2–TRAF6 complex and leads to the inhibition of TRAF6 ubiquitination, which negatively regulates the TLR4-mediated signaling for NF-κB activation. [ABSTRACT FROM AUTHOR]

Selective autophagy is a catabolic route that turns over specific cellular material for degradation by lysosomes, and whose role in the regulation of innate immunity is largely unexplored. Here, we show that the apical kinase of the Drosophila immune deficiency (IMD) pathway Tak1, as well as its co-activator Tab2, are both selective autophagy substrates that interact with the autophagy protein Atg8a. We also present a role for the Atg8a-interacting protein Sh3px1 in the downregulation of the IMD pathway, by facilitating targeting of the Tak1/Tab2 complex to the autophagy platform through its interaction with Tab2. Our findings show the Tak1/Tab2/Sh3px1 interactions with Atg8a mediate the removal of the Tak1/Tab2 signaling complex by selective autophagy. This in turn prevents constitutive activation of the IMD pathway in Drosophila. This study provides mechanistic insight on the regulation of innate immune responses by selective autophagy. [Display omitted] • Yeast-two-hybrid screening identifies Atg8a-interacting proteins • TAK1 interacts with Atg8a via an LIR motif • TAB2 interacts with Atg8a and SH3PX1 • Selective autophagic degradation of TAK1/TAB2 complex is fine-tuned by SH3PX1 Tsapras et al. perform a yeast-two-hybrid screen to identify Atg8a-interacting proteins in Drosophila. They show that Atg8a interacts with TAK1 via an LIR motif. Atg8a also interacts with TAB2. TAB2 interacts with SH3PX1. Selective autophagic degradation of TAK1/TAB2 complex is fine-tuned by SH3PX1 to control innate immune responses. [ABSTRACT FROM AUTHOR]

TGF-β-activated kinase 1 (TAK1), a member of the MAPKKK family, is thought to be a key modulator of the inducible transcription factors NF-κB and AP-1 and, therefore, plays a crucial role in regulating the genes that mediate inflammation. Although in vitro biochemical studies have revealed the existence of a TAK1 complex, which includes TAK1 and the adapter proteins TAB1 and TAB2, it remains unclear which members of this complex are essential for signaling. To analyze the function of TAK1 in vivo, we have deleted the Tak1 gene in mice, with the resulting phenotype being early embryonic lethality. Using embryonic fibroblasts lacking TAK1, TAB1, or TAB2, we have found that TNFR1, IL-1R, TLR3, and TLR4-mediated NF-κB and AP-1 activation are severely impaired in Tak1m/m cells, but they are normal in Tab1-/- and Tab2-/- cells. In addition, Tak1m/m cells are highly sensitive to TNF-induced apoptosis. TAK1 mediates IKK activation in TNF-α and IL-1 signaling pathways, where it functions downstream of RIP1-TRAF2 and MyD88-IRAK1-TRAF6, respectively. However, TAK1 is not required for NF-κB activation through the alternative pathway following LT-β signaling. In the TGF-β signaling pathway, TAK1 deletion leads to impaired NF-κB and c-Jun N-terminal kinase (JNK) activation without impacting Smad2 activation or TGF-β-induced gene expression. Therefore, our studies suggests that TAK1 acts as an upstream activating kinase for IKKβ and JNK, but not IKKα, revealing an unexpectedly specific role of TAK1 in inflammatory signaling pathways. [ABSTRACT FROM AUTHOR]