Functions of innate immune cells and commensal bacteria in gut homeostasis
The intestinal immune system remains unresponsive to beneficial microbes and dietary antigens while activating pro-inflammatory responses against pathogens for host defence. In intestinal mucosa, abnormal activation of innate immunity, which directs adaptive immune responses, causes the onset and/or progression of inflammatory bowel diseases. Thus, innate immunity is finely regulated in the gut. Multiple innate immune cell subsets have been identified in both murine and human intestinal lamina propria. Some innate immune cells play a key role in the maintenance of gut homeostasis by preventing inappropriate adaptive immune...
Source: Journal of Biochemistry - January 25, 2016 Category: Biochemistry Authors: Kayama, H., Takeda, K. Tags: JB Special Reviews-Crosstalk between the Intestinal Immune System and Gut Commensal Microbiota Source Type: research
Characterization of Aes nuclear foci in colorectal cancer cells
Amino-terminal enhancer of split (Aes) is a member of Groucho/Transducin-like enhancer (TLE) family. Aes is a recently found metastasis suppressor of colorectal cancer (CRC) that inhibits Notch signalling, and forms nuclear foci together with TLE1. Although some Notch-associated proteins are known to form subnuclear bodies, little is known regarding the dynamics or functions of these structures. Here, we show that Aes nuclear foci in CRC observed under an electron microscope are in a rather amorphous structure, lacking surrounding membrane. Investigation of their behaviour during the cell cycle by time-lapse cinematography...
Source: Journal of Biochemistry - January 7, 2016 Category: Biochemistry Authors: Itatani, Y., Sonoshita, M., Kakizaki, F., Okawa, K., Stifani, S., Itoh, H., Sakai, Y., Taketo, M. M. Tags: Regular Papers Source Type: research
Endosomal escape efficiency of fusogenic B18 and B55 peptides fused with anti-EGFR single chain Fv as estimated by nuclear translocation
In this study, we constructed FP-fused anti-epidermal growth factor receptor (EGFR) single-chain Fv (αEGFR[scFv]) proteins and evaluated their endosomal escape efficiency by utilizing a nuclear localization signal). When the FP-fused αEGFR[scFv] proteins were incubated with A431 cells, the estimated endosomal escape efficiency of αEGFR[scFv]-B18 was significantly higher than that of αEGFR[scFv] alone, suggesting that the B18 peptide facilitates endosomal escape of the conjugated scFv in cis. Moreover, αEGFR[scFv]-B55 promoted the intracellular uptake of co-administered eGFP and dextrans in tra...
Source: Journal of Biochemistry - January 7, 2016 Category: Biochemistry Authors: Niikura, K., Horisawa, K., Doi, N. Tags: Regular Papers Source Type: research
The role of intra-domain disulfide bonds in heat-induced irreversible denaturation of camelid single domain VHH antibodies
Camelid-derived single domain VHH antibodies are highly heat resistant, and the mechanism of heat-induced VHH denaturation predominantly relies on the chemical modification of amino acids. Although chemical modification of disulfide bonds has been recognized as a cause for heat-induced denaturation of many proteins, there have been no mutagenesis studies, in which the number of disulfide bonds was controlled. In this article, we examined a series of mutants of two different VHHs with single, double or no disulfide bonds, and scrutinized the effects of these disulfide bond modifications on VHH denaturation. With the excepti...
Source: Journal of Biochemistry - January 7, 2016 Category: Biochemistry Authors: Akazawa-Ogawa, Y., Uegaki, K., Hagihara, Y. Tags: Regular Papers Source Type: research
Control of Trx1 redox state modulates protection against methyl methanesulfonate-induced DNA damage via stabilization of p21
In this study, we used the DNA-damaging agent methyl methanesulfonate (MMS) to investigate the protective effects of Trx1 against DNA damage and cell death in HEK293 cells. We found that MMS application caused dose-dependent changes in the Trx1 redox state determined by redox western blotting. At lower concentrations, both reduced and oxidized Trx1 were observed, whereas the reduced band was fully oxidized at the higher concentration. Trx1 overexpression and small interfering RNA knockdown in cells revealed that reduced Trx1 after exposure to lower doses of MMS attenuated DNA damage, assessed by comet assay, and level of t...
Source: Journal of Biochemistry - January 7, 2016 Category: Biochemistry Authors: Gu, L., Gao, W., Yang, H. M., Wang, B. B., Wang, X. N., Xu, J., Zhang, H. Tags: Regular Papers Source Type: research
PqqE from Methylobacterium extorquens AM1: a radical S-adenosyl-L-methionine enzyme with an unusual tolerance to oxygen
Methylobacterium extorquens AM1 is an aerobic facultative methylotroph known to secrete pyrroloquinoline quinone (PQQ), a cofactor of a number of bacterial dehydrogenases, into the culture medium. To elucidate the molecular mechanism of PQQ biosynthesis, we are focusing on PqqE which is believed to be the enzyme catalysing the first reaction of the pathway. PqqE belongs to the radical S-adenosyl-l-methionine (SAM) superfamily, in which most, if not all, enzymes are very sensitive to dissolved oxygen and rapidly inactivated under aerobic conditions. We here report that PqqE from M. extorquens AM1 is markedly oxygen-tolerant...
Source: Journal of Biochemistry - January 7, 2016 Category: Biochemistry Authors: Saichana, N., Tanizawa, K., Pechousek, J., Novak, P., Yakushi, T., Toyama, H., Frebortova, J. Tags: Regular Papers Source Type: research
Cloning and characterization of the first polysaccharide lyase family 6 oligoalginate lyase from marine Shewanella sp. Kz7
In this study, we cloned an oligoalginate lyase gene, oalS6, from Shewanella sp. Kz7 and expressed it in Escherichia coli. The PL family 6 oligoalginate lyase (OalS6) has no significant sequence similarity with other known oligoalginate lyases. OalS6 contains a chondroitinase-like domain and was assigned to the PL family 6. This lyase is an exo-type oligoalginate lyase and prefer to depolymerize polyG block into 2, 4, 5, 6-tetrahydroxytetrahydro-2H-pyran-2-carboxylic acid. All of these results indicate that OalS6 is a novel oligoalginate lyase that is structurally and functionally different from other known oligoalginate l...
Source: Journal of Biochemistry - January 7, 2016 Category: Biochemistry Authors: Li, S., Wang, L., Han, F., Gong, Q., Yu, W. Tags: Regular Papers Source Type: research
Effect of trastuzumab interchain disulfide bond cleavage on Fc{gamma} receptor binding and antibody-dependent tumour cell phagocytosis
In this study, the disulfide bonds within the IgG1 trastuzumab (TRA), which is specific for HER2, were cleaved by mild S-sulfonation or by mild reduction followed by S-alkylation with three different reagents. The cleavage did not change the binding activities of TRA to HER2-bearing SK-BR-3 cells. The binding activities of TRA to FcRIIA and FcRIIB were greatly enhanced by modification with mild reduction and S-alkylation with ICH2CONH2 or N-(4-aminophenyl) maleimide, while the binding activities of TRA to FcRI and FcRIIIA were decreased by any of the four modifications. However, the interchain disulfide bond cleavage by th...
Source: Journal of Biochemistry - January 7, 2016 Category: Biochemistry Authors: Suzuki, M., Yamanoi, A., Machino, Y., Ootsubo, M., Izawa, K.-i., Kohroki, J., Masuho, Y. Tags: Regular Papers Source Type: research
Nucleotide carriers for anti-tumour actinomycin antibiotics
We have investigated a number of complexes of 7-aminoactinomycin D (7AAMD), with its potential carriers: caffeine, folic acid (FA), purine bases—guanine and adenine, pyrimidine base—thymine and with fragmented DNA to determine more stable and suitable complex. The process of binding of the fluorescent antibiotic with clusters of caffeine, guanine, adenine, thymine and with fragmented DNA was accompanied by a considerable long-wavelength shift in excitation spectrum. The energy of interaction between phenoxazine hetero-cycle of 7AAMD and chromophores of the carriers studied has been found. In the case of 7AAMD w...
Source: Journal of Biochemistry - January 7, 2016 Category: Biochemistry Authors: Vekshin, N. L., Kovalev, V. I. Tags: Regular Papers Source Type: research
Quantification of mutation-derived bias for alternate mating functionalities of the Saccharomyces cerevisiae Ste2p pheromone receptor
Although well documented for mammalian G-protein-coupled receptors, alternate functionalities and associated alternate signalling remain to be unequivocally established for the Saccharomyces cerevisiae pheromone Ste2p receptor. Here, evidence supporting alternate functionalities for Ste2p is re-evaluated, extended and quantified. In particular, strong mating and constitutive signalling mutations, focusing on residues S254, P258 and S259 in TM6 of Ste2p, are stacked and investigated in terms of their effects on classical G-protein-mediated signal transduction associated with cell cycle arrest, and alternatively, their impac...
Source: Journal of Biochemistry - January 7, 2016 Category: Biochemistry Authors: Choudhary, P., Loewen, M. C. Tags: Regular Papers Source Type: research
Interaction of a novel fluorescent GTP analogue with the small G-protein K-Ras
A novel fluorescent guanosine 5'-triphosphate (GTP) analogue, 2'(3')-O-{6-(N-(7-nitrobenz-2-oxa-l,3-diazol-4-yl)amino) hexanoic}-GTP (NBD-GTP), was synthesized and utilized to monitor the effect of mutations in the functional region of mouse K-Ras. The effects of the G12S, A59T and G12S/A59T mutations on GTPase activity, nucleotide exchange rates were compared with normal Ras. Mutation at A59T resulted in reduction of the GTPase activity by 0.6-fold and enhancement of the nucleotide exchange rate by 2-fold compared with normal Ras. On the other hand, mutation at G12S only slightly affected the nucleotide exchange rate and ...
Source: Journal of Biochemistry - January 7, 2016 Category: Biochemistry Authors: Iwata, S., Masuhara, K., Umeki, N., Sako, Y., Maruta, S. Tags: Regular Papers Source Type: research
Functional implication of archaeal homologues of human RNase P protein pair Pop5 and Rpp30
PhoPop5 and PhoRpp30 in the hyperthermophilic archaeon Pyrococcus horikoshii, homologues of human ribonuclease P (RNase P) proteins hPop5 and Rpp30, respectively, fold into a heterotetramer [PhoRpp30–(PhoPop5)2–PhoRpp30], which plays a crucial role in the activation of RNase P RNA (PhopRNA). Here, we examined the functional implication of PhoPop5 and PhoRpp30 in the tetramer. Surface plasmon resonance (SPR) analysis revealed that the tetramer strongly interacts with an oligonucleotide including the nucleotide sequence of a stem-loop SL3 in PhopRNA. In contrast, PhoPop5 had markedly reduced affinity to SL3, wher...
Source: Journal of Biochemistry - January 7, 2016 Category: Biochemistry Authors: Hamasaki, M., Hazeyama, K., Iwasaki, F., Ueda, T., Nakashima, T., Kakuta, Y., Kimura, M. Tags: Regular Papers Source Type: research
Regulation of the TMEPAI promoter by TCF7L2: the C-terminal tail of TCF7L2 is essential to activate the TMEPAI gene
We previously found that TCF7L2 could activate the TMEPAI gene efficiently, whereas LEF1 could not nearly augment its transcription. When we comprehended the functional difference(s) between TCF7L2 and LEF1 with respect to the activation of the TMEPAI gene, the C-terminal tail of TCF7L2 was needed to reveal its transcriptional activity as well as its interaction with Smad3. Consistently, both TCF7/TCF7L2 and LEF1/TCF7L2 chimeric proteins exhibited an activity similar to TCF7L2 in transcription and Smad3 binding in contrast with LEF1 and TCF7. Our data elaborated on the diverse activity among TCF/LEF family members with res...
Source: Journal of Biochemistry - January 7, 2016 Category: Biochemistry Authors: Nakano, N., Kato, M., Itoh, S. Tags: Rapid Communication Source Type: research
Novel working hypothesis for pathogenesis of hematological malignancies: combination of mutations-induced cellular phenotypes determines the disease (cMIP-DD)
Recent progress in high-speed sequencing technology has revealed that tumors harbor novel mutations in a variety of genes including those for molecules involved in epigenetics and splicing, some of which were not categorized to previously thought malignancy-related genes. However, despite thorough identification of mutations in solid tumors and hematological malignancies, how these mutations induce cell transformation still remains elusive. In addition, each tumor usually contains multiple mutations or sometimes consists of multiple clones, which makes functional analysis difficult. Fifteen years ago, it was proposed that ...
Source: Journal of Biochemistry - January 7, 2016 Category: Biochemistry Authors: Kitamura, T., Watanabe-Okochi, N., Enomoto, Y., Nakahara, F., Oki, T., Komeno, Y., Kato, N., Doki, N., Uchida, T., Kagiyama, Y., Togami, K., Kawabata, K. C., Nishimura, K., Hayashi, Y., Nagase, R., Saika, M., Fukushima, T., Asada, S., Fujino, T., Izawa, Y Tags: JB Special Reviews-Cell Fate Decision, and its Underlying Molecular Mechanisms Source Type: research
Regulation of maintenance DNA methylation via histone ubiquitylation
DNA methylation is one of the most stable but dynamically regulated epigenetic marks that act as determinants of cell fates during embryonic development through regulation of various forms of gene expression. DNA methylation patterns must be faithfully propagated throughout successive cell divisions in order to maintain cell-specific function. We have recently demonstrated that Uhrf1-dependent ubiquitylation of histone H3 at lysine 23 is critical for Dnmt1 recruitment to DNA replication sites, which catalyzes the conversion of hemi-methylated DNA to fully methylated DNA. In this review, we provide an overview of recent pro...
Source: Journal of Biochemistry - January 7, 2016 Category: Biochemistry Authors: Nishiyama, A., Yamaguchi, L., Nakanishi, M. Tags: JB Special Reviews-Cell Fate Decision, and its Underlying Molecular Mechanisms Source Type: research
