The NFkB activation domain is 14-amino-acid-long variant of the 9aaTAD.

The nine-amino-acid transactivation domains (9aaTAD) was identified in numerous transcription factors including Gal4, p53, E2A, MLL, c-Myc, N-Myc, and also in SP, KLF, and SOX families. Most of the 9aaTAD domains interact with the KIX domain of transcription mediators MED15 and CBP to activate transcription. The NFkB activation domain occupied the same position on the KIX domain as the 9aaTADs of MLL, E2A, and p53. Binding of the KIX domain is established by the two-point interaction involving 9aaTAD positions p3-4 and p6-7. The NFkB primary binding region (positions p3-4) is almost identical with MLL and E2A, but secondary NFkB binding region differs by the position and engages the distal NFkB region p10-11. Thus, the NFkB activation domain is five amino acids longer than the other 9aaTADs. The NFkB activation domain includes an additional region, which we called the Omichinski Insert extending activation domain length to 14 amino acids. By deletion, we demonstrated that Omichinski Insert is an entirely non-essential part of NFkB activation domain. In summary, we recognized the NFkB activation domain as prolonged 9aaTAD conserved in evolution from humans to amphibians.

Expansions of tumor-reactive Vdelta1 gamma-delta T cells in newly diagnosed patients with chronic myeloid leukemia.

Recent studies have underscored the importance of gamma-delta (γδ) T cells in mediating potent MHC-unrestricted cytotoxicity in numerous malignancies. Here, we analyzed Vδ1 and Vδ2 γδ T cell subsets in newly diagnosed chronic myeloid leukemia (CML) patients (n = 40) who had initiated tyrosine kinase inhibitor (TKI) therapy including imatinib (n = 22), nilotinib (n = 14) and dasatinib (n = 4). Patient peripheral blood samples were analyzed at diagnosis and monitored prospectively at 3, 6, 12 and 18 months post-TKI. γδ T cells isolated from healthy donors and CML patients were used against K562, LAMA-84 and KYO-1 cell lines and against primary CML cells in cytotoxicity assays. We found large expansions of Vδ1 and Vδ2 T cells in patients at diagnosis compared to age-matched healthy donors (n = 40) (p < 0.0001). The γδ T cell reconstitution in patients on imatinib and also on nilotinib showed significant reductions of Vδ1 T cell and Vδ2 T cell absolute counts at 3 months compared to diagnosis. Importantly, Vδ1 and Vδ2 T absolute cell counts remained at normal levels from 3 months throughout the follow-up. Next, we observed susceptibility to specific lysis of primary CML tumor cells by Vδ1 T cells from healthy donors. Furthermore, we determined inherent cytotoxic reactivity by autologous patients' Vδ1 T lymphocytes against primary CML tumor cells. Finally, the TCR clonality profiles showed in CML patients mostly polyclonal repertoires regardless of the TKI. Our results provide further evidence into γδ T cell antileukemia immunity in CML that might be beneficial for long-term disease control and treatment outcome.

Cryptic inhibitory regions nearby activation domains.

Previously, the Nine amino acid TransActivation Domain (9aaTAD) was identified in the Gal4 region 862-870 (DDVYNYLFD). Here, we identified 9aaTADs in the distal Gal4 orthologs by our prediction algorithm and found their conservation in the family. The 9aaTAD function as strong activators was demonstrated. We identified adjacent Gal4 region 871-811 (DEDTPPNPKKE) as a natural 9aaTAD inhibitory domain located at the extreme Gal4 terminus. Moreover, we identified conserved Gal4 region 172-185 (FDWSEEDDMSDGLP), which was capable to reverse the 9aaTAD inhibition. In conclusion, our results uncover the existence of the cryptic inhibitory domains, which need to be carefully implemented in all functional studies with transcription factors to avoid incorrect conclusions.

Clozapine Reverses Dysfunction of Glutamatergic Neurons Derived From Clozapine-Responsive Schizophrenia Patients.

The cellular pathology of schizophrenia and the potential of antipsychotics to target underlying neuronal dysfunctions are still largely unknown. We employed glutamatergic neurons derived from induced pluripotent stem cells (iPSC) obtained from schizophrenia patients with known histories of response to clozapine and healthy controls to decipher the mechanisms of action of clozapine, spanning from molecular (transcriptomic profiling) and cellular (electrophysiology) levels to observed clinical effects in living patients. Glutamatergic neurons derived from schizophrenia patients exhibited deficits in intrinsic electrophysiological properties, synaptic function and network activity. Deficits in K+ and Na+ currents, network behavior, and glutamatergic synaptic signaling were restored by clozapine treatment, but only in neurons from clozapine-responsive patients. Moreover, neurons from clozapine-responsive patients exhibited a reciprocal dysregulation of gene expression, particularly related to glutamatergic and downstream signaling, which was reversed by clozapine treatment. Only neurons from clozapine responders showed return to normal function and transcriptomic profile. Our results underscore the importance of K+ and Na+ channels and glutamatergic synaptic signaling in the pathogenesis of schizophrenia and demonstrate that clozapine might act by normalizing perturbances in this signaling pathway. To our knowledge this is the first study to demonstrate that schizophrenia iPSC-derived neurons exhibit a response phenotype correlated with clinical response to an antipsychotic. This opens a new avenue in the search for an effective treatment agent tailored to the needs of individual patients.

Blocking of EphA2 on Endometrial Tumor Cells Reduces Susceptibility to Vδ1 Gamma-Delta T-Cell-Mediated Killing.

Background: Endometriosis is a common gynecological disease characterized by the presence of endometrial tissue outside the uterus causing chronic inflammation, severe pain, and infertility. However, the innate immunity of gamma-delta (γδ) T lymphocytes in endometriosis has not been characterized. Women with endometriosis present numerous endocrine and immune dysfunctions and elevated risk for endometrial, ovarian, and breast cancers. The tyrosine kinase EphA2 is often overexpressed in cancer including endometrial carcinoma. Methods: We analyzed Vδ1 and Vδ2 γδ T cells in peripheral blood and paired peritoneal fluid samples in endometriosis patients (n = 19) and compared the counts with that of age- and sex-matched healthy donors (n = 33) using flow cytometry. Vδ1 and Vδ2 T cells isolated from healthy donors were used against KLE, RL-95, and Ishikawa endometrial tumor cells in 4 h flow cytometric cytotoxicity assays. The EphA2 blocking studies were performed using antibody, small-molecule inhibitor ALW-II-41-27, and the CRISPR/Cas9. Results: We determined Vδ1 T cells substantially reduced in patients' peripheral blood (p < 0.01) and peritoneal fluid (p < 0.001). No differences were found for circulating Vδ2 T cells compared with peritoneal fluid samples. We observed inherent cytotoxic reactivity of Vδ1 and Vδ2 γδ T lymphocytes against endometrial tumor cells. Importantly, we found reduced specific lysis of EphA2-positive cell lines KLE and RL-95 by Vδ1 T cells in the EphA2 antibody blocking studies and by the EphA2 inhibitor. Furthermore, Vδ1 T-cell-mediated killing was significantly decreased in RL-95 cell EPHA2 knockout. Finally, potent cytolytic activity exerted by Vδ1 T cells was significantly reduced in EPHA2 knockouts in renal A-498 and colon HT-29 carcinoma cell lines. Conclusions: We determined variable levels of Vδ1 and Vδ2 γδ T cells in endometriosis patients. We observed inherent cytotoxic reactivity of γδ T-cell subsets against endometrial cell lines. Specifically, we found that blocking of EphA2 expression resulted in significant inhibition of endometrial tumor killing mediated by Vδ1 γδ T cells. These results suggest that EphA2 is involved in tumor cell lysis and contributes to susceptibility to Vδ1 γδ T cells cytotoxic reactivity.

Plasmacytoid Dendritic Cells in Patients with MGUS and Multiple Myeloma.

BACKGROUND: Plasmacytoid dendritic cells (pDCs) play prominent roles in mediating innate and adaptive immune responses. However, it is unclear how pDCs contribute to the immunosuppressive tumor microenvironment described in multiple myeloma (MM). METHODS: Newly diagnosed myeloma patients (MM, n = 37) were analyzed to determine the pDC counts in comparison to peripheral blood (PB, n = 53) and bone marrow (BM, n = 10) samples of age-matched healthy donors (HD) using flow cytometry. Second, proliferation of myeloma tumor cells in the presence of freshly isolated pDCs was examined. Third, production of IFNα by pDCs co-cultured with MM cells was determined by intracellular staining. RESULTS: We found a highly significant reduction of circulating pDCs (p < 0.0001) and in bone marrow (p < 0.0001) of MM patients compared to HD. We also observed a significant decrease of pDCs (p = 0.004) in BM in patients with monoclonal gammopathy of undetermined significance (MGUS, n = 12). Importantly, we determined that pDCs promote proliferation specifically of MM cells and not the stromal cells and that pDCs secrete IFNα upon co-culture with MM tumor cells. CONCLUSIONS: Our results show altered pDC frequencies in the BM microenvironment in MGUS and MM patients at diagnosis. We showed the tumor-promoting function of pDCs that may mediate immune deficiencies affecting long-term disease control and treatment outcome.

Universal two-point interaction of mediator KIX with 9aaTAD activation domains.

The nine-amino-acid activation domain (9aaTAD) is defined by a short amino acid pattern including two hydrophobic regions (positions p3-4 and p6-7). The KIX domain of mediator transcription CBP interacts with the 9aaTAD domains of transcription factors MLL, E2A, NF-kB, and p53. In this study, we analyzed the 9aaTADs-KIX interactions by nuclear magnetic resonance. The positions of three KIX helixes α1-α2-α3 are influenced by sterically-associated hydrophobic I611, L628, and I660 residues that are exposed to solvent. The positions of two rigid KIX helixes α1 and α2 generate conditions for structural folding in the flexible KIX-L12-G2 regions localized between them. The three KIX I611, L628, and I660 residues interact with two 9aaTAD hydrophobic residues in positions p3 and p4 and together build a hydrophobic core of five residues (5R). Numerous residues in 9aaTAD position p3 and p4 could provide this interaction. Following binding of the 9aaTAD to KIX, the hydrophobic I611, L628, and I660 residues are no longer exposed to solvent and their position changes inside the hydrophobic core together with position of KIX α1-α2-α3 helixes. The new positions of the KIX helixes α1 and α2 allow the KIX-L12-G2 enhanced formation. The second hydrophobic region of the 9aaTAD (positions p6 and p7) provides strong binding with the KIX-L12-G2 region. Similarly, multiple residues in 9aaTAD position p6 and p7 could provide this interaction. In conclusion, both 9aaTAD regions p3, p4 and p6, p7 provide co-operative and highly universal binding to mediator KIX. The hydrophobic core 5R formation allows new positions of the rigid KIX α-helixes and enables the enhanced formation of the KIX-L12-G2 region. This contributes to free energy and is the key for the KIX-9aaTAD binding. Therefore, the 9aaTAD-KIX interactions do not operate under the rigid key-and-lock mechanism what explains the 9aaTAD natural variability.

The evolution of the 9aaTAD domain in Sp2 proteins: inactivation with valines and intron reservoirs.

The universal nine-amino-acid transactivation domains (9aaTADs) have been identified in numerous transcription activators. Here, we identified the conserved 9aaTAD motif in all nine members of the specificity protein (SP) family. Previously, the Sp1 transcription factor has been defined as a glutamine-rich activator. We showed by amino acid substitutions that the glutamine residues are completely dispensable for 9aaTAD function and are not conserved in the SP family. We described the origin and evolutionary history of 9aaTADs. The 9aaTADs of the ancestral Sp2 gene became inactivated in early chordates. We next discovered that an accumulation of valines in 9aaTADs inactivated their transactivation function and enabled their strict conservation during evolution. Subsequently, in chordates, Sp2 has duplicated and created new paralogs, Sp1, Sp3, and Sp4 (the SP1-4 clade). During chordate evolution, the dormancy of the Sp2 activation domain lasted over 100 million years. The dormant but still intact ancestral Sp2 activation domains allowed diversification of the SP1-4 clade into activators and repressors. By valine substitution in the 9aaTADs, Sp1 and Sp3 regained their original activator function found in ancestral lower metazoan sea sponges. Therefore, the vertebrate SP1-4 clade could include both repressors and activators. Furthermore, we identified secondary 9aaTADs in Sp2 introns present from fish to primates, including humans. In the gibbon genome, introns containing 9aaTADs were used as exons, which turned the Sp2 gene into an activator. Similarly, we identified introns containing 9aaTADs used conditionally as exons in the (SP family-unrelated) transcription factor SREBP1, suggesting that the intron-9aaTAD reservoir is a general phenomenon.

Nuclear hormone receptors: Ancient 9aaTAD and evolutionally gained NCoA activation pathways.

In higher metazoans, the nuclear hormone receptors activate transcription trough their specific adaptors, nuclear hormone receptor adaptors NCoA, which are absent in lower metazoans. The Nine amino acid TransActivation Domain, 9aaTAD, was reported for a large number of the transcription activators that recruit general mediators of transcription. In this study, we demonstrated that the 9aaTAD from NHR-49 receptor of nematode C.elegans activates transcription as a small peptide. We showed that the ancient 9aaTAD domains are conserved in the nuclear hormone receptors including human HNF4, RARa, VDR and PPARg. Also their small 9aaTAD peptides effectively activated transcription in absence of the NCoA adaptors. We also showed that adjacent H11 domains in ancient and modern hormone receptors have an inhibitory effect on their 9aaTAD function.

The inositol phosphatase SHIP2 enables sustained ERK activation downstream of FGF receptors by recruiting Src kinases.

Sustained activation of extracellular signal-regulated kinase (ERK) drives pathologies caused by mutations in fibroblast growth factor receptors (FGFRs). We previously identified the inositol phosphatase SHIP2 (also known as INPPL1) as an FGFR-interacting protein and a target of the tyrosine kinase activities of FGFR1, FGFR3, and FGFR4. We report that loss of SHIP2 converted FGF-mediated sustained ERK activation into a transient signal and rescued cell phenotypes triggered by pathologic FGFR-ERK signaling. Mutant forms of SHIP2 lacking phosphoinositide phosphatase activity still associated with FGFRs and did not prevent FGF-induced sustained ERK activation, demonstrating that the adaptor rather than the catalytic activity of SHIP2 was required. SHIP2 recruited Src family kinases to the FGFRs, which promoted FGFR-mediated phosphorylation and assembly of protein complexes that relayed signaling to ERK. SHIP2 interacted with FGFRs, was phosphorylated by active FGFRs, and promoted FGFR-ERK signaling at the level of phosphorylation of the adaptor FRS2 and recruitment of the tyrosine phosphatase PTPN11. Thus, SHIP2 is an essential component of canonical FGF-FGFR signal transduction and a potential therapeutic target in FGFR-related disorders.

The 9aaTAD Is Exclusive Activation Domain in Gal4.

The Gal4 protein is a well-known prototypic acidic activator that has multiple activation domains. We have previously identified a new activation domain called the nine amino acid transactivation domain (9aaTAD) in Gal4 protein. The family of the 9aaTAD activators currently comprises over 40 members including p53, MLL, E2A and other members of the Gal4 family; Oaf1, Pip2, Pdr1 and Pdr3. In this study, we revised function of all reported Gal4 activation domains. Surprisingly, we found that beside of the activation domain 9aaTAD none of the previously reported activation domains had considerable transactivation potential and were not involved in the activation of transcription. Our results demonstrated that the 9aaTAD domain is the only decisive activation domain in the Gal4 protein. We found that the artificial peptides included in the original Gal4 constructs were results of an unintended consequence of cloning that were responsible for the artificial transcriptional activity. Importantly, the activation domain 9aaTAD, which is the exclusive activation domain in Gal4, is also the central part of a conserved sequence recognized by the inhibitory protein Gal80. We propose a revision of the Gal4 regulation, in which the activation domain 9aaTAD is directly linked to both activation function and Gal80 mediated inhibition.

The 9aaTAD Transactivation Domains: From Gal4 to p53.

The family of the Nine amino acid Transactivation Domain, 9aaTAD family, comprises currently over 40 members. The 9aaTAD domains are universally recognized by the transcriptional machinery from yeast to man. We had identified the 9aaTAD domains in the p53, Msn2, Pdr1 and B42 activators by our prediction algorithm. In this study, their competence to activate transcription as small peptides was proven. Not surprisingly, we elicited immense 9aaTAD divergence in hundreds of identified orthologs and numerous examples of the 9aaTAD species' convergence. We found unforeseen similarity of the mammalian p53 with yeast Gal4 9aaTAD domains. Furthermore, we identified artificial 9aaTAD domains generated accidentally by others. From an evolutionary perspective, the observed easiness to generate 9aaTAD transactivation domains indicates the natural advantage for spontaneous generation of transcription factors from DNA binding precursors.

Do human B-lymphocytes avoid aging until 60 years?

Broad changes in human innate and adaptive immunity are associated with advanced age. The age-related alteration of gene expression was reported for both T and B lymphocytes. We analysed the genome-wide expression profiles (n=20) of naive and whole B cell populations from young and early aged healthy donors under 60 years. We revealed large homogeneity of all analysed genome-wide expression profiles but did not identified any significant gene deregulation between young (30-45 years) and early aged healthy donors (50-60 years). We argue that B cells avoid the aging program on molecular level until 60 years of age. Our results demonstrate the potential of hematopoietic stem cells to generate uncompromised lymphocytes in early elderly. These are very encouraging findings for the general health and the immunity maintenance would not need any intervention to naive B cells. Rather, a suitable immune stimulation in healthy body environment warrants further research into aging of older elderly.

Shared structural features of the 9aaTAD family in complex with CBP.

A number of transactivation domains for transcription factors including p53, E2A/HEB, MLL, cMyb, CREB, FOXO3, Gcn4, Oaf1 and Pdr1 have been reported to interact with the KIX domain of general transcriptional mediators CBP, p300 or MED15. Most of those factors belong to the already established Nine amino acid Transactivation Domain (9aaTAD) family. By using available structural data, we found binding analogy for the 9aaTAD in the MLL-KIX and also E2A/HEB-KIX complexes. We recognized two distinct TAD formations in the KIX complex. In the E2A/HEB-KIX complex, the leucine position is determined by the prolonged helical structure including the 9aaTAD and the leucine (long-helical TAD). However in the MLL-KIX complex, the equal position of 9aaTAD and proximal leucine is achieved differently by leucine-turn-helix structural architecture. Furthermore, the FOXO3-KIX complex shares structural analogy with the E2A-KIX complex in respect of both 9aaTAD and proximal leucine. Next, from (i) sequence alignment of the identified 9aaTADs in p53, E2A/HEB and MLL proteins and (ii) the resolved structure of the MLL-KIX and E2A/HEB-KIX complexes, we generated a plausible structural model for p53 that could be used also for other members of the 9aaTAD family. The position of 9aaTADs in Oaf1-, Pdr1- and Gcn4-MED15 KIX complexes and 9aaTAD composition are in good agreement with E2A, MLL, FOXO3 and p53. Analyses of structural data in this study define fundamental structural requirements and shed more light on the ambiguous 9aaTAD domain.

Functionally suppressive CD8 T regulatory cells are increased in patients with multiple myeloma: a cause for immune impairment.

BACKGROUND: Multiple myeloma (MM) is a plasma cell malignancy frequently associated with impaired immune cell numbers and functions. In MM, several studies have previously shown that CD4 regulatory T (Treg) cells hamper effector T cell functions and enhance immune dysfunction. In this study, we aimed to prove the presence of functionally suppressive Treg cells expressing CD8 phenotype (CD8 Treg cells) in MM. To the best of our knowledge, this has not been reported previously in MM. METHODS: We analyzed CD8 Treg cells and their transcription factor FoxP3 from 64 newly diagnosed MM patients using flow cytometry and real time-polymerase chain reaction (RT-PCR). RNA profile of cytokines in CD8 Treg cells was also assessed using RT-PCR. CD8 Treg cells from 5 MM patients and 5 healthy donors were functionally evaluated using proliferation assays. RESULTS: CD8 Treg cells (CD8+CD25hi+) were significantly elevated in MM patients (P<0.0001), and their transcription factor FoxP3 expression was also higher in MM (P<0.0001) compared to healthy donors which was evidenced by flow cytometry and RT-PCR analyses. CD8 Treg cells negatively correlated with total lymphocyte count (P = 0.016). Functional studies revealed that CD8 Treg cells isolated from MM patients and healthy donors inhibited proliferation of CD4 T cells in a concentration dependent manner. In the presence of CD8 Treg cells in proliferation assays, level of IFN-γ was decreased but not IL-10. CD4 T cells from MM patients secreted abnormal level of IL-10 compared to healthy donors (P = 0.01) in proliferation assays without CD8 Treg cells. RNA profile of cytokines from CD8 Treg cells did not differ significantly between MM patients and healthy donors. CONCLUSIONS: These findings show the presence of increased number of functionally suppressive CD8 Treg cells in MM patients. We believe that these suppressive CD8 Treg cells might enhance immune impairment and disease progression in MM.

Conditional knockdown of hMRS2 results in loss of mitochondrial Mg(2+) uptake and cell death.

The human gene MRS2L encodes a mitochondrial protein distantly related to CorA Mg(2+) transport proteins. Constitutive shRNA-mediated knockdown of hMRS2 in human HEK-293 cell line was found here to cause death. To further study its role in Mg(2+) transport, we have established stable cell lines with conditionally expressing shRNAs directed against hMRS2L. The cells expressing shRNA for several generations exhibited lower steady-state levels of free mitochondrial Mg(2+) ([Mg(2+)](m)) and reduced capacity of mitochondrial Mg(2+) uptake than control cells. Long-term expression of shRNAs resulted in loss of mitochondrial respiratory complex I, decreased mitochondrial membrane potential and cell death. We conclude that hMrs2 is the major transport protein for Mg (+) uptake into mitochondria and that expression of hMrs2 is essential for the maintenance of respiratory complex I and cell viability.

A novel 9-amino-acid transactivation domain in the C-terminal part of Sox18.

Sox transcription factors are members of the Sry-related protein family that play multiple roles mainly during development. Sox18 has been implicated in the development of hair follicles as well as the blood and lymphatic vasculature, due to the identification of mutations that result in the ragged phenotype in mice, and in the hypotrichosis lymphedema telangiectasia syndrome in humans. Sox18 consists of an N-terminal high-mobility group DNA binding and a central transactivation domain, followed by a C-terminal region of unknown function. We show here that this C-terminal domain consists of three blocks that are highly conserved within a subgroup of the Sox family, and that the central so-called charged block comprises an additional strong transactivating domain. This activity can be pinpointed to a recently described 9aa transactivation motif that mediates the interaction with the transcriptional cofactor TAF9. These result can explain previously controversial data on the functional consequences of Sox18 mutations in mice and humans.

Nine-amino-acid transactivation domain: establishment and prediction utilities.

Here we describe the establishment and prediction utilities for a novel nine-amino-acid transactivation domain, 9aa TAD, that is common to the transactivation domains of a large number of yeast and animal transcription factors. We show that the 9aa TAD motif is required for the function of the transactivation domain of Gal4 and the related transcription factors Oaf1 and Pip2. The 9aa TAD possesses an autonomous transactivation activity in yeast and mammalian cells. Using sequence alignment and experimental data we derived a pattern that can be used for 9aa TAD prediction. The pattern allows the identification of 9aa TAD in other Gal4 family members or unrelated yeast, animal, and viral transcription factors. Thus, the 9aa TAD represents the smallest known denominator for a broad range of transcription factors. The wide occurrence of the 9aa TAD suggests that this domain mediates conserved interactions with general transcriptional cofactors. A computational search for the 9aa TAD is available online from National EMBnet-Node Austria at http://www.at.embnet.org/toolbox/9aatad/.