scholarly journals Single-point mutations of a lysine residue change function of Bax and Bcl-xL expressed in Bax- and Bak-less mouse embryonic fibroblasts: novel insights into the molecular mechanisms of Bax-induced apoptosis

2010 ◽  
Vol 18 (3) ◽  
pp. 427-438 ◽  
Author(s):  
I Szabò ◽  
M Soddemann ◽  
L Leanza ◽  
M Zoratti ◽  
E Gulbins
2004 ◽  
Vol 83 (11) ◽  
pp. 837-842 ◽  
Author(s):  
G. Spagnuolo ◽  
C. Mauro ◽  
A. Leonardi ◽  
M. Santillo ◽  
R. Paternò ◽  
...  

The cytotoxicity of dental monomers has been widely investigated, but the underlying mechanisms have not been elucidated. We studied the molecular mechanisms involved in cell death induced by HEMA. In human primary fibroblasts, HEMA induced a dose-dependent apoptosis that was confirmed by the activation of caspases-8, -9, and -3. We found an increase of reactive oxygen species (ROS) and NF-κB activation after HEMA exposure. Blocking of ROS production by anti-oxidants had no direct influence on apoptosis caused by HEMA, but inhibition of NF-κB increased the fraction of apoptotic cells. Accordingly, mouse embryonic fibroblasts (MEF) from p65−/− mice were more susceptible to HEMA-induced apoptosis than were wild-type controls. Our results indicate that exposure to HEMA triggers apoptosis and that this mechanism is not directly dependent upon redox signaling. Nevertheless, ROS induction by HEMA activates NF-κB, which exerts a protective role in counteracting apoptosis.


Author(s):  
Keiko Doi ◽  
Takahiro Fujimoto ◽  
Midori Koyanagi ◽  
Toshiyuki Tsunoda ◽  
Yoko Tanaka ◽  
...  

AbstractZFAT was originally identified as an immune-related transcriptional regulator containing 18 C2H2-type zinc-finger domains and one AT-hook. ZFAT is highly conserved among species and functions as an anti-apoptotic molecule in the lymphoblastic leukemia cell line, MOLT-4. We recently demonstrated that ZFAT is an essential molecule for hematopoietic differentiation in blood islands through the direct regulation of particular transcriptional factors, including Tal1, for endothelial cell assembly, and for the branch point formation of capillary-like structures. However, the molecular mechanisms underlying the anti-apoptotic function of ZFAT remain unknown. Here, we report that ZFAT knockdown by small interfering RNA induced apoptosis in mouse embryonic fibroblasts (MEFs). This response had been similarly observed for MOLT-4 cells. To explore the molecular mechanisms for ZFAT in anti-apoptotic function in both MEFs and MOLT-4 cells, microarray expression analysis and quantitative RT-PCR were done. Of interest was that Bcl-2 and Il6st were identified as commonly down-regulated genes by the depletion of ZFAT for both MEFs and MOLT-4 cells. These results suggest that ZFAT is a critical molecule for cell survival in MEFs and MOLT-4 cells at least in part through the regulation of the apoptosis involved in the BCL-2- and IL6st-mediated pathways. Further elucidation of the molecular functions for ZFAT might shed light on the cellular programs in the mesoderm-derived cells.


2019 ◽  
Author(s):  
Nobutaka Fujieda ◽  
Miho Yuasa ◽  
Yosuke Nishikawa ◽  
Genji Kurisu ◽  
Shinobu Itoh ◽  
...  

Cupin superfamily proteins (TM1459) work as a macromolecular ligand framework with a double-stranded beta-barrel structure ligating to a Cu ion through histidine side chains. Variegating the first coordination sphere of TM1459 revealed that H52A and H54A/H58A mutants effectively catalyzed the diastereo- and enantio-selective Michael addition reaction of nitroalkanes to an α,β-unsaturated ketone. Moreover, in silico substrate docking signified C106N and F104W single-point mutations, which inverted the diastereoselectivity of H52A and further improved the stereoselectivity of H54A/H58A, respectively.


2021 ◽  
Author(s):  
Marisa L. Martino ◽  
Stephen N. Crooke ◽  
Marianne Manchester ◽  
M.G. Finn

2017 ◽  
Vol 474 (18) ◽  
pp. 3189-3205 ◽  
Author(s):  
Ashoka Chary Taviti ◽  
Tushar Kant Beuria

Cell division in bacteria is a highly controlled and regulated process. FtsZ, a bacterial cytoskeletal protein, forms a ring-like structure known as the Z-ring and recruits more than a dozen other cell division proteins. The Min system oscillates between the poles and inhibits the Z-ring formation at the poles by perturbing FtsZ assembly. This leads to an increase in the FtsZ concentration at the mid-cell and helps in Z-ring positioning. MinC, the effector protein, interferes with Z-ring formation through two different mechanisms mediated by its two domains with the help of MinD. However, the mechanism by which MinD triggers MinC activity is not yet known. We showed that MinD directly interacts with FtsZ with an affinity stronger than the reported MinC–FtsZ interaction. We determined the MinD-binding site of FtsZ using computational, mutational and biochemical analyses. Our study showed that MinD binds to the H10 helix of FtsZ. Single-point mutations at the charged residues in the H10 helix resulted in a decrease in the FtsZ affinity towards MinD. Based on our findings, we propose a novel model for MinCD–FtsZ interaction, where MinD through its direct interaction with FtsZ would trigger MinC activity to inhibit FtsZ functions.


2006 ◽  
Vol 340 (3) ◽  
pp. 792-799 ◽  
Author(s):  
Motofumi Tanaka ◽  
Motoko Nagano-Fujii ◽  
Lin Deng ◽  
Satoshi Ishido ◽  
Kiyonao Sada ◽  
...  

2007 ◽  
Vol 67 (4 suppl) ◽  
pp. 813-818 ◽  
Author(s):  
CS. Trinca ◽  
HF. Waldemarin ◽  
E. Eizirik

The Neotropical otter is one of the least known otter species, and it is considered to be threatened to various degrees throughout its geographic range. Little information exists on the ecological characteristics of this species, and no genetic study has been published about it until now, hampering the design of adequate conservation strategies for its populations. To contribute with genetic information to comprehensive conservation efforts on behalf of L. longicaudis, we characterized the molecular diversity of the 5’ portion of the mtDNA control region in samples from this species collected in Southern and Southeastern Brazil. The sequence analysis revealed a high level of haplotype diversity (h = 0.819; SE = 0.0052) and nucleotide variability ranging from 0.0039 to 0.0067. One of the sampled haplotypes was the most common in both regions and, from this sequence, several other (locally occurring) haplotypes could be derived by single point mutations. No significant genetic differentiation was observed between the Southern and Southeastern regions.


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