Nck-interacting Kinase Research Articles

Abstract A132: Development of a small-molecule inhibitor targeting the Wnt signaling pathway.

Abstract Wnt signaling is a major force driving colorectal carcinogenesis, but only a small number of druggable target molecules in the Wnt pathway have been found. Our recent series of proteomic studies has revealed that various classes of nuclear proteins participate in the β-catenin and T-cell factor-4 (TCF-4) complex and modulate the activity of Wnt signalling. Those included fusion/translocated in liposarcoma (FUS/TLS) (1), poly(ADP-ribose) polymerase-1 (PARP-1) (2), Ku70/Ku80 (3), DNA topoisomerase IIα (Topo IIα) (4), splicing factor-1 (SF1) (5), Ran (ras-related nuclear protein), RanBP2 (Ran binding protein-2), and RanGAP1 (Ran GTPase-activating protein-1) (6), Traf2- and Nck-interacting kinase (TNIK) (7). Among these proteins, TNIK protein kinase attracted our current interest because various small-molecule kinase inhibitors have been applied successfully to cancer treatment. TNIK was an activating kinase for TCF-4, and colorectal cancer cells are highly dependent upon the expression and catalytic activity of TNIK for proliferation (7). High-throughput screening of a kinase-focused compound library (>10,000 compounds) against recombinant TNIK identified a lead candidate that inhibited the kinase activity of TNIK with an IC50 value of 8.6 nM and the transcriptional activity of TCF-4. TNIK is a feasible drug target in the Wnt signaling pathway. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A132. Citation Format: Tesshi Yamada, Mari Masuda, Masaaki Sawa. Development of a small-molecule inhibitor targeting the Wnt signaling pathway. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A132.

Multiple cytoskeletal pathways and PI3K signaling mediate CDC-42-induced neuronal protrusion in C. elegans

Rho GTPases are key regulators of cellular protrusion and are involved in many developmental events including axon guidance during nervous system development. Rho GTPase pathways display functional redundancy in developmental events, including axon guidance. Therefore, their roles can often be masked when using simple loss-of-function genetic approaches. As a complement to loss-of-function genetics, we constructed a constitutively activated CDC-42(G12V) expressed in C. elegans neurons. CDC-42(G12V) drove the formation of ectopic lamellipodial and filopodial protrusions in the PDE neurons, which resembled protrusions normally found on migrating growth cones of axons. We then used a candidate gene approach to identify molecules that mediate CDC-42(G12V)-induced ectopic protrusions by determining if loss of function of the genes could suppress CDC-42(G12V). Using this approach, we identified 3 cytoskeletal pathways previously implicated in axon guidance, the Arp2/3 complex, UNC-115/abLIM, and UNC-43/Ena. We also identified the Nck-interacting kinase MIG-15/NIK and p21-activated kinases (PAKs), also implicated in axon guidance. Finally, PI3K signaling was required, specifically the Rictor/mTORC2 branch but not the mTORC1 branch that has been implicated in other aspects of PI3K signaling including stress and aging. Our results indicate that multiple pathways can mediate CDC-42-induced neuronal protrusions that might be relevant to growth cone protrusions during axon pathfinding. Each of these pathways involves Rac GTPases, which might serve to integrate the pathways and coordinate the multiple CDC-42 pathways. These pathways might be relevant to developmental events such as axon pathfinding as well as disease states such as metastatic melanoma.

Dynamic change of TNIK in response to tumor necrosis factor alpha in a TRAF2-dependent manner

TNIK (TRAF2- and NCK-interacting kinase) was named because of its association with TRAF2 (tumor necrosis factor receptor-associated factor 2). But the relationship between TNIK and TRAF2 is still elusive, in addition to which the involvement of TNIK in JNK activation by TNFα hints that there maybe a linkage between TNIK and TRAF2. In this work, we illustrated that TNIK protein levels were dynamic in response to TNFα stimulation in an ubiquitin-dependent manner. Further study showed that TRAF2 negatively modulated the levels of TNIK by regulating the ubiquitin conjugation. In conclusion, our data may give evidence that dynamic change of TNIK offers a way to protect cells from outside stimulus.

Discovery of 4-phenyl-2-phenylaminopyridine based TNIK inhibitors

A series of compounds based on a 4-phenyl-2-phenylaminopyridine scaffold that are potent and selective inhibitors of Traf2- and Nck-interacting kinase (TNIK) activity are described. These compounds were used as tools to test the importance of TNIK kinase activity in signaling and proliferation in Wnt-activated colorectal cancer cells. The results indicate that pharmacological inhibition of TNIK kinase activity has minimal effects on either Wnt/TCF4/β-catenin-driven transcription or viability. The findings suggest that the kinase activity of TNIK may be less important to Wnt signaling than other aspects of TNIK function, such as its putative role in stabilizing the TCF4/β-catenin transcriptional complex.

TNiK Is Required for Postsynaptic and Nuclear Signaling Pathways and Cognitive Function

Traf2 and NcK interacting kinase (TNiK) contains serine-threonine kinase and scaffold domains and has been implicated in cell proliferation and glutamate receptor regulation in vitro. Here we report its role in vivo using mice carrying a knock-out mutation. TNiK binds protein complexes in the synapse linking it to the NMDA receptor (NMDAR) via AKAP9. NMDAR and metabotropic receptors bidirectionally regulate TNiK phosphorylation and TNiK is required for AMPA expression and synaptic function. TNiK also organizes nuclear complexes and in the absence of TNiK, there was a marked elevation in GSK3β and phosphorylation levels of its cognate phosphorylation sites on NeuroD1 with alterations in Wnt pathway signaling. We observed impairments in dentate gyrus neurogenesis in TNiK knock-out mice and cognitive testing using the touchscreen apparatus revealed impairments in pattern separation on a test of spatial discrimination. Object-location paired associate learning, which is dependent on glutamatergic signaling, was also impaired. Additionally, TNiK knock-out mice displayed hyperlocomotor behavior that could be rapidly reversed by GSK3β inhibitors, indicating the potential for pharmacological rescue of a behavioral phenotype. These data establish TNiK as a critical regulator of cognitive functions and suggest it may play a regulatory role in diseases impacting on its interacting proteins and complexes.

Agonistic and Antagonistic Roles for TNIK and MINK in Non-Canonical and Canonical Wnt Signalling

Wnt signalling is a key regulatory factor in animal development and homeostasis and plays an important role in the establishment and progression of cancer. Wnt signals are predominantly transduced via the Frizzled family of serpentine receptors to two distinct pathways, the canonical ß-catenin pathway and a non-canonical pathway controlling planar cell polarity and convergent extension. Interference between these pathways is an important determinant of cellular and phenotypic responses, but is poorly understood. Here we show that TNIK (Traf2 and Nck-interacting kinase) and MINK (Misshapen/NIKs-related kinase) MAP4K signalling kinases are integral components of both canonical and non-canonical pathways in Xenopus. xTNIK and xMINK interact and are proteolytically cleaved in vivo to generate Kinase domain fragments that are active in signal transduction, and Citron-NIK-Homology (CNH) Domain fragments that are suppressive. The catalytic activity of the Kinase domain fragments of both xTNIK and xMINK mediate non-canonical signalling. However, while the Kinase domain fragments of xTNIK also mediate canonical signalling, the analogous fragments derived from xMINK strongly antagonize this signalling. Our data suggest that the proteolytic cleavage of xTNIK and xMINK determines their respective activities and is an important factor in controlling the balance between canonical and non-canonical Wnt signalling in vivo.

The Germinal Center Kinase TNIK Is Required for Canonical NF-κB and JNK Signaling in B-Cells by the EBV Oncoprotein LMP1 and the CD40 Receptor

Author SummaryThe germinal center kinase family member TNIK was discovered in a yeast-two-hybrid screen for interaction partners of the adapter proteins TRAF2 and Nck, and here we show it is one of the missing molecular players in two key signaling pathways in B-lymphocytes. We found that TNIK is crucial for the activities of the CD40 receptor on Bcells and its viral mimic, the latent membrane protein 1 (LMP1) of Epstein-Barr virus (EBV). EBV is a human DNA tumor virus that is associated with various malignancies. It targets and transforms B-cells by hijacking the cellular signaling machinery via its oncogene LMP1. In normal Bcell physiology, the CD40 receptor is central to the immune response by mediating B-cell activation and proliferation. TNIK turns out to be an organizer of the LMP1- and CD40-induced signaling complexes by interacting with the TRAF6 adapter protein, well known for its role in linking distinct signaling pathways. Through this mechanism the two receptors depend on TNIK to activate the canonical NF-κB and JNK signal transduction pathways, which are important for the physiological activation of B-cells (a process that enables antibody production), as well as for their transformation into tumor cells. TNIK thus constitutes a key player in the transmission of physiological and pathological signals in human B-cells that might serve as a future therapeutic target against B-cell malignancies.

Mig-38, a novel gene that regulates distal tip cell turning during gonadogenesis in C. elegans hermaphrodites

In Caenorhabditis elegans gonad morphogenesis, the final U-shapes of the two hermaphrodite gonad arms are determined by migration of the distal tip cells (DTCs). These somatic cells migrate in opposite directions on the ventral basement membrane until specific extracellular cues induce turning from ventral to dorsal and then centripetally toward the midbody region on the dorsal basement membrane. To dissect the mechanism of DTC turning, we examined the role of a novel gene, F40F11.2/mig-38, whose depletion by RNAi results in failure of DTC turning so that DTCs continue their migration away from the midbody region. mig-38 is expressed in the gonad primordium, and expression continues throughout DTC migration where it acts cell-autonomously to control DTC turning. RNAi depletion of both mig-38 and ina-1, which encodes an integrin adhesion receptor, enhanced the loss of turning phenotype indicating a genetic interaction between these genes. Furthermore, the integrin-associated protein MIG-15/Nck-interacting kinase (NIK) works with MIG-38 to direct DTC turning as shown by mig-38 RNAi with the mig-15(rh80) hypomorph. These results indicate that MIG-38 enhances the role of MIG-15 in integrin-dependent DTC turning. Knockdown of talin, a protein that is important for integrin activation, causes the DTCs to stop migration prematurely. When both talin and MIG-38 were depleted by RNAi treatment, the premature stop phenotype was suppressed. This suppression effect was reversed upon additional depletion of MIG-15 or its binding partner NCK-1. These results suggest that both talin and the MIG-15/NCK-1 complex promote DTC motility and that MIG-38 may act as a negative regulator of the complex. We propose a model to explain the dual role of MIG-38 in motility and turning.

Abstract 904: The TNIK kinase is a potential target in non-small cell lung and gastric cancer

Abstract Traf2- and Nck-interacting kinase (TNIK) is one of germinal centre kinase (GCK) family members involved in cytoskeleton organization and neuronal dendrite extension. Emerging evidence indicated that TNIK is essential in activation of WNT pathway and colon cancer growth. To search for novel genetic aberrations that drive carcinogenesis, we performed microarray-based comparative hybridization (aGCH) to screen gene copy number variations in primary tumor samples and found TNIK gene is amplified in 19.2 % (29/151) of Chinese non-small cell lung cancer and 7 % (8/106) of Chinese gastric cancer patients. Interestingly, the amplification in NSCLC is highly enriched in squamous NSCLC patients (41.1%, 28/68). Theses amplifications were confirmed by fluorescence in situ hybridization (FISH) analysis. To further understand the function of TNIK gene amplification, PAMC82 human gastric cancer and T47D colon cancer cell lines with TNIK amplification were identified. RNA-interference-mediated silencing of TNIK resulted in significantly reduced cell growth and increased cell death in the TNIK amplified, but not in the non-amplified, tested cell lines. Together, our results suggest that TNIK is a novel therapeutic target in NSCLC and gastric cancer and TNIK amplification can be potentially used for patient selection. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 904. doi:1538-7445.AM2012-904

CD27 signaling on chronic myelogenous leukemia stem cells activates Wnt target genes and promotes disease progression

Chronic myelogenous leukemia (CML) results from a chromosomal translocation in hematopoietic stem or early progenitor cells that gives rise to the oncogenic BCR/ABL fusion protein. Clinically, CML has a chronic phase that eventually evolves into an accelerated stage and blast crisis. A CML-specific immune response is thought to contribute to the control of disease. Whether the immune system can also promote disease progression is not known. In the present study, we investigated the possibility that the TNF receptor family member CD27 is present on leukemia stem cells (LSCs) and mediates effects of the immune system on CML. In a mouse model of CML, BCR/ABL+ LSCs and leukemia progenitor cells were found to express CD27. Binding of CD27 by its ligand, CD70, increased expression of Wnt target genes in LSCs by enhancing nuclear localization of active β-catenin and TRAF2- and NCK-interacting kinase (TNIK). This resulted in increased proliferation and differentiation of LSCs. Blocking CD27 signaling in LSCs delayed disease progression and prolonged survival. Furthermore, CD27 was expressed on CML stem/progenitor cells in the bone marrow of CML patients, and CD27 signaling promoted growth of BCR/ABL+ human leukemia cells by activating the Wnt pathway. Since expression of CD70 is limited to activated lymphocytes and dendritic cells, our results reveal a mechanism by which adaptive immunity contributes to leukemia progression. In addition, targeting CD27 on LSCs may represent an attractive therapeutic approach to blocking the Wnt/β-catenin pathway in CML.

MIG-15 and ERM-1 promote growth cone directional migration in parallel to UNC-116 and WVE-1

Neurons require precise targeting of their axons to form a connected network and a functional nervous system. Although many guidance receptors have been identified, much less is known about how these receptors signal to direct growth cone migration. We used Caenorhabditis elegans motoneurons to study growth cone directional migration in response to a repellent UNC-6 (netrin homolog) guidance cue. The evolutionarily conserved kinase MIG-15 [homolog of Nck-interacting kinase (NIK)] regulates motoneuron UNC-6-dependent repulsion through unknown mechanisms. Using genetics and live imaging techniques, we show that motoneuron commissural axon morphology defects in mig-15 mutants result from impaired growth cone motility and subsequent failure to migrate across longitudinal obstacles or retract extra processes. To identify new genes acting with mig-15, we screened for genetic enhancers of the mig-15 commissural phenotype and identified the ezrin/radixin/moesin ortholog ERM-1, the kinesin-1 motor UNC-116 and the actin regulator WVE-1 complex. Genetic analysis indicates that mig-15 and erm-1 act in the same genetic pathway to regulate growth cone migration and that this pathway functions in parallel to the UNC-116/WVE-1 pathway. Further, time-lapse imaging of growth cones in mutants suggests that UNC-116 might be required to stimulate protrusive activity at the leading edge, whereas MIG-15 and ERM-1 maintain low activity at the rear edge. Together, these results support a model in which the MIG-15 kinase and the UNC-116-WVE-1 complex act on opposite sides of the growth cone to promote robust directional migration.

Quantitative phosphoproteomics of transforming growth factor‐β signaling in colon cancer cells

The transforming growth factor-β (TGF-β) signaling pathway progresses through a series of protein phosphorylation regulated steps. Smad4 is a key mediator of the classical TGF-β signaling pathway; however, reports suggest that TGF-β can activate other cellular pathways independent of Smad4. By investigating the TGF-β-regulated phosphoproteome, we aimed to uncover new functions controlled by TGF-β. We applied titanium dioxide to enrich phosphopeptides from stable isotope labeling with amino acids in cell culture (SILAC)-labeled SW480 cells stably expressing Smad4 and profiled them by mass spectrometry. TGF-β stimulation for 30 min resulted in the induction of 17 phosphopeptides and the repression of 8 from a total of 149 unique phosphopeptides. Proteins previously not known to be phosphorylated by TGF-β including programmed cell death protein 4, nuclear ubiquitous casein and cyclin-dependent kinases substrate, hepatoma-derived growth factor and cell division kinases amongst others were induced following TGF-β stimulation, while the phosphorylation of TRAF2 and NCK-interacting protein kinase are examples of proteins whose phosphorylation status was repressed. This phosphoproteomic screen has identified new TGF-β-modulated phosphorylation responses in colon carcinoma cells.

The enormous influence of TNIK knockdown on intracellular signals and cell survival

Basic cellular activities and coordinated cell actions are governed by intracellular signals, among which the Wnt signaling cascade plays an important role in tissue polarity and cell adhesion or movement through the activation of c-Jun N-terminal kinase (JNK) pathway. As one of the central transcriptional factors, Traf2- and Nck-interacting kinase (TNIK) mediates the transactivation of Wnt target genes and promotes the activity of c-Jun N-terminus kinase (JNK)2 when overexpressed. To further understand the function of TNIK, changes in intracellular signals were detected in colon cancer cell lines using a knockdown strategy. In this study, we found that the short-hairpin RNA-mediated knockdown of TNIK decreased the expressions of CD44, c-MYC and cyclin D1, which was consistent with the results of a TCF-4 reporter assay. Our data showed, for the first time, that the activation of both JNK1 and JNK2 by TNFα could be blocked through TNIK knockdown, which dampened the AP1 luciferase activity accordingly. In addition, adenovirus mediated the downregulation of TNIK-triggered intrinsic apoptosis in SW480 cells by activating caspase-9 and PARP-1. We conclude that TNIK is essential for the activation of both the canonical Wnt pathway and the JNK pathway, and serves as a pro-survival factor.

The psychiatric disease risk factors DISC1 and TNIK interact to regulate synapse composition and function

Disrupted in schizophrenia 1 (DISC1), a genetic risk factor for multiple serious psychiatric diseases including schizophrenia, bipolar disorder and autism, is a key regulator of multiple neuronal functions linked to both normal development and disease processes. As these diseases are thought to share a common deficit in synaptic function and architecture, we have analyzed the role of DISC1 using an approach that focuses on understanding the protein-protein interactions of DISC1 specifically at synapses. We identify the Traf2 and Nck-interacting kinase (TNIK), an emerging risk factor itself for disease, as a key synaptic partner for DISC1, and provide evidence that the DISC1-TNIK interaction regulates synaptic composition and activity by stabilizing the levels of key postsynaptic density proteins. Understanding the novel DISC1-TNIK interaction is likely to provide insights into the etiology and underlying synaptic deficits found in major psychiatric diseases.

Traf2- and Nck-interacting Kinase Is Essential for Canonical Wnt Signaling in Xenopus Axis Formation

Wnt signaling pathways play important roles in various stages of developmental events and several aspects of adult homeostasis. Aberrant activation of Wnt signaling has also been associated with several types of cancer. We have recently identified Traf2- and Nck-interacting kinase (TNIK) as a novel activator of Wnt signaling through a comprehensive proteomic approach in human colorectal cancer cell lines. TNIK is an activating kinase for T-cell factor-4 (TCF4) and essential for the beta-catenin-TCF4 transactivation and colorectal cancer growth. Here, we report the essential role of TNIK in Wnt signaling during Xenopus development. We found that Xenopus TNIK (XTNIK) was expressed maternally and that the functional knockdown of XTNIK by catalytically inactive XTNIK (K54R) or antisense morpholino oligonucleotides resulted in significant malformations with a complete loss of head and axis structures. XTNIK enhanced beta-catenin-induced axis duplication and the expression of beta-catenin-TCF target genes, whereas knockdown of XTNIK inhibited it. XTNIK was recruited to the promoter region of beta-catenin-TCF target genes in a beta-catenin-dependent manner. These results demonstrate that XTNIK is an essential factor for the transcriptional activity of the beta-catenin-TCF complex and dorsal axis determination in Xenopus embryos.

Erratum: Organizing the cell cortex: the role of ERM proteins

Nature Reviews Molecular Cell Biology 11, 276–287 (2010). On page 277 of the above article, there is a mistake with the definition and alternative name of NIK. This should be NCK-interacting kinase (also known as MAP4K4) and not NF-κβ-inducing kinase (also known as MAP3K14) as stated. We apologize for any confusion caused to the readers.

Traf2- and Nck-Interacting Kinase Is Essential for Wnt Signaling and Colorectal Cancer Growth

T-cell factor-4 (TCF4) is a transcription factor essential for maintaining the undifferentiated status and self-renewal of intestinal epithelial cells. It has therefore been considered that constitutive activation of TCF4 by aberrant Wnt signaling is a major force driving colorectal carcinogenesis. We previously identified Traf2- and Nck-interacting kinase (TNIK) as one of the proteins that interact with TCF4 in colorectal cancer cells, but its functional significance has not been elucidated. Here, we report that TNIK is an activating kinase for TCF4 and essential for colorectal cancer growth. TNIK, but not its catalytically inactive mutant, phosphorylated the conserved serine 154 residue of TCF4. Small interfering RNA targeting TNIK inhibited the proliferation of colorectal cancer cells and the growth of tumors produced by injecting colorectal cancer cells s.c. into immunodeficient mice. The growth inhibition was abolished by restoring the catalytic domain of TNIK, thus confirming that its enzyme activity is essential for the maintenance of colorectal cancer growth. Several ATP-competing kinase inhibitors have been applied to cancer treatment and have shown significant activity. Our findings suggest TNIK as a feasible target for pharmacologic intervention to ablate aberrant Wnt signaling in colorectal cancer.

Abstract 1224: TNIK is a protein kinase essential for Wnt signaling and colorectal carcinogenesis

Abstract Aberrant transactivation of a certain set of target genes of T-cell factor-4 (TCF4), a member of the TCF/lymphoid enhancer factor (LEF) family of transcription factors, by Wnt signaling has been considered crucial in colorectal carcinogenesis. Through a comprehensive proteome approach we identified Traf2- and Nck-interacting kinase (TNIK) as a novel activator for TCF4. Here we report the functional involvement of TNIK in Wnt signaling and human colon cancer growth in vitro and in vivo. Methods: Proteins of two colorectal cancer cell lines, HCT-116 and DLD1, were immunoprecipitated with anti-TCF-4 antibody and analyzed directly by nano-flow liquid chromatography and mass spectrometry. Results: TNIK was detected in the immunoprecipitates with anti-TCF4 or anti-β-catenin antibody, but not with control IgG. Conversely, β-catenin and TCF4 proteins were immunoprecipitated with anti-TNIK antibody, indicating that TCF4, β-catenin, and TNIK proteins form a complex in colorectal cancer cells. TCF4 protein was phosphorylated by TNIK, but not by the catalytically inactive mutant of TNIK with substitution (K54R) of the conserved lysine 54 residue in the ATP-binding pocket of the kinase domain. Knockdown of TNIK by siRNA against TNIK suppressed the TCF/LEF transcriptional activity and proliferation of DLD1 and HCT-116 cells. The expression of known target genes of the β-catenin and TCF/LEF complexes, such as axis inhibitor-2 (AXIN2), c-myc (MYC), c-jun (JUN), and matrilysin (MMP7), except for cyclin D1 (CCND1), was significantly reduced by transient transfection with siRNA against TNIK. siRNA targeting TNIK inhibited the growth of tumors produced by injecting colorectal cancer cells subcutaneously into immunodeficient mice, and the growth inhibition was abolished by restoring the catalytic domain of TNIK. Conclusions: Wnt signaling is a major force driving colorectal carcinogenesis. More than 80% of colorectal cancers show mutation of the APC gene, resulting in accumulation of β-catenin and constitutive activation of Wnt signaling. Because restoration of the loss of function resulting from mutation of the APC gene is not a realistic approach, we have been searching for molecules involved in Wnt signaling downstream of APC, especially in the nucleus, that could be potential drug targets. We identified TNIK as the activating kinase of the TCF4 and β-catenin transcriptional complex. Several ATP-competing kinase inhibitors have been applied to cancer treatment and have shown significant activity. A new drug targeting TNIK might be effective for suppressing aberrant Wnt signaling and colorectal cancer growth.

The kinase TNIK is an essential activator of Wnt target genes

Wnt signalling maintains the undifferentiated state of intestinal crypt/progenitor cells through the TCF4/beta-catenin-activating transcriptional complex. In colorectal cancer, activating mutations in Wnt pathway components lead to inappropriate activation of the TCF4/beta-catenin transcriptional programme and tumourigenesis. The mechanisms by which TCF4/beta-catenin activate key target genes are not well understood. Using a proteomics approach, we identified Tnik, a member of the germinal centre kinase family as a Tcf4 interactor in the proliferative crypts of mouse small intestine. Tnik is recruited to promoters of Wnt target genes in mouse crypts and in Ls174T colorectal cancer cells in a beta-catenin-dependent manner. Depletion of TNIK and expression of TNIK kinase mutants abrogated TCF-LEF transcription, highlighting the essential function of the kinase activity in Wnt target gene activation. In vitro binding and kinase assays show that TNIK directly binds both TCF4 and beta-catenin and phosphorylates TCF4. siRNA depletion of TNIK followed by expression array analysis showed that TNIK is an essential, specific activator of Wnt transcriptional programme. This kinase may present an attractive candidate for drug targeting in colorectal cancer.

TRAF2 and NCK interacting kinase (TNIK)

TRAF2 and NCK interacting kinase (TNIK)