scholarly journals Evaluation of the Reactivity and Receptor Competition of HLA-G Isoforms toward Available Antibodies: Implications of Structural Characteristics of HLA-G Isoforms

2019 ◽  
Vol 20 (23) ◽  
pp. 5947 ◽  
Author(s):  
Atsushi Furukawa ◽  
Manami Meguro ◽  
Rika Yamazaki ◽  
Hiroshi Watanabe ◽  
Ami Takahashi ◽  
...  

The human leucocyte antigen (HLA)-G, which consists of seven splice variants, is a tolerogenic immune checkpoint molecule. It plays an important role in the protection of the fetus from the maternal immune response by binding to inhibitory receptors, including leukocyte Ig-like receptors (LILRs). Recent studies have also revealed that HLA-G is involved in the progression of cancer cells and the protection from autoimmune diseases. In contrast to its well characterized isoform, HLA-G1, the binding activities of other major HLA-G isoforms, such as HLA-G2, toward available anti-HLA-G antibodies are only partially understood. Here, we investigate the binding specificities of anti-HLA-G antibodies by using surface plasmon resonance. MEM-G9 and G233 showed strong affinities to HLA-G1, with a nM range for their dissociation constants, but did not show affinities to HLA-G2. The disulfide-linker HLA-G1 dimer further exhibited significant avidity effects. On the other hand, 4H84 and MEM-G1, which can be used for the Western blotting of HLA-G isoforms, can bind to native HLA-G2, while MEM-G9 and G233 cannot. These results reveal that HLA-G2 has a partially intrinsically disordered structure. Furthermore, MEM-G1, but not 4H84, competes with the LILRB2 binding of HLA-G2. These results provide novel insight into the functional characterization of HLA-G isoforms and their detection systems.

2014 ◽  
Vol 15 (6) ◽  
pp. 10350-10364 ◽  
Author(s):  
María Teresa-Rodrigo ◽  
Juliane Eckhold ◽  
Beatriz Puisac ◽  
Andreas Dalski ◽  
María Gil-Rodríguez ◽  
...  

1988 ◽  
Vol 8 (4) ◽  
pp. 1518-1524 ◽  
Author(s):  
D Soldati ◽  
D Schümperli

Oligonucleotides derived from the spacer element of the histone RNA 3' processing signal were used to characterize mouse U7 small nuclear RNA (snRNA), i.e., the snRNA component active in 3' processing of histone pre-mRNA. Under RNase H conditions, such oligonucleotides inhibited the processing reaction, indicating the formation of a DNA-RNA hybrid with a functional ribonucleoprotein component. Moreover, these oligonucleotides hybridized to a single nuclear RNA species of approximately 65 nucleotides. The sequence of this RNA was determined by primer extension experiments and was found to bear several structural similarities with sea urchin U7 snRNA. The comparison of mouse and sea urchin U7 snRNA structures yields some further insight into the mechanism of histone RNA 3' processing.


2002 ◽  
Vol 283 (2) ◽  
pp. C587-C598 ◽  
Author(s):  
Annette Hambrock ◽  
Regina Preisig-Müller ◽  
Ulrich Russ ◽  
Anke Piehl ◽  
Peter J. Hanley ◽  
...  

ATP-sensitive K+ (KATP) channels are composed of pore-forming Kir6.x subunits and regulatory sulfonylurea receptor (SUR) subunits. SURs are ATP-binding cassette proteins with two nucleotide-binding folds (NBFs) and binding sites for sulfonylureas, like glibenclamide, and for channel openers. Here we report the identification and functional characterization of four novel splice forms of guinea pig SUR1. Three splice forms originate from alternative splicing of the region coding for NBF1 and lack exons 17 (SUR1Δ17), 19 (SUR1Δ19), or both (SUR1Δ17Δ19). The fourth (SUR1C) is a COOH-terminal SUR1-fragment formed by exons 31–39 containing the last two transmembrane segments and the COOH terminus of SUR1. RT-PCR analysis showed that these splice forms are expressed in several tissues with strong expression of SUR1C in cardiomyocytes. Confocal microscopy using enhanced green fluorescent protein-tagged SUR or Kir6.x did not provide any evidence for involvement of these splice forms in the mitochondrial KATP channel. Only SUR1 and SUR1Δ17 showed high-affinity binding of glibenclamide ( K d≈ 2 nM in the presence of 1 mM ATP) and formed functional KATPchannels upon coexpression with Kir6.2.


Botany ◽  
2013 ◽  
Vol 91 (8) ◽  
pp. 495-504 ◽  
Author(s):  
Hao Xu ◽  
Janice E.K. Cooke ◽  
Janusz J. Zwiazek

In mycorrhizal associations, water transport properties of the fungal hyphae may have a profound effect on water transport of the host plant. The importance of aquaporins, water-transporting members of the major intrinsic protein (MIP) family, in facilitating water transport has been widely acknowledged and extensively studied in plants. However, until recently, relatively little was known about the structure, function, and regulation of fungal MIPs. The rapid increase in the number of sequenced fungal genomes, including Laccaria bicolor and other mycorrhizal fungi, has enabled functional and comparative genomic investigations to delineate the role that fungal MIPs play in mycorrhizal-facilitated plant water transport. Phylogenic analysis of 229 fungal MIPs from 88 species revealed that MIPs of mycorrhizal fungal species fall into four clusters delineated by functionally characterized fungal MIPs: the orthodox aquaporins, the aquaglyceroporins, the facultative fungal aquaporins, and the X intrinsic proteins. This comparative genomics analysis, together with in silico structural characterization of predicted MIPs and recently published functional characterization of MIPs from a small number of ectomycorrhizal and arbuscular mycorrhizal species, provide new insight into MIP gene families of mycorrhizal fungi and possible roles for fungal aquaporins in water relations of mycorrhizal plant–fungus symbioses.


Author(s):  
Shefali Mishra ◽  
Pradeep Sharma ◽  
Rajender Singh ◽  
ratan Tiwari ◽  
Gyanendra Pratap Singh

The SnRK gene family is a key regulator playing an important role in plant stress response by phosphorylating the target protein to regulate the signalling pathways. The function of SnRK gene family has been reported in many species but is limited to Triticum asetivum. In this study, SnRK gene family in the wheat genome was identified and its structural characteristics were described. One hundred forty-seven SnRK genes distributed across 21 chromosomes were identified in the Triticum aestivum genome and categorised into three subgroups (SnRK1/2/3) based on phylogenetic analyses and domain types. The gene intron-exon structure and protein-motif composition of SnRKs were similar within each subgroup but different amongst the groups. Gene duplication between the wheat, Arabidopsis, rice and barley genomes was also investigated in order to get insight into the evolutionary aspects of the TaSnRK family genes. SnRK genes showed differential expression patterns in leaves, roots, spike, and grains. Redundant stress-related cis-elements were also found in the promoters of 129 SnRK genes and their expression levels varied widely following drought, ABA and light regulated elements. In particular, TaSnRK2.11 had higher and increased expression under the abiotic stresses and can be a candidate gene for the abiotc stress tolerance. The findings will aid in the functional characterization of TaSnRK genes for further research.


2021 ◽  
Author(s):  
Gisela Rangel-Tescas ◽  
Cecilia Cervantes ◽  
Miguel A Cervantes-Rocha ◽  
Esteban Suarez-Delgado ◽  
Anastazia T Banaszak ◽  
...  

Voltage-dependent proton-permeable channels are membrane proteins mediating a number of important physiological functions. Here we report the presence of a gene encoding for Hv1 voltage-dependent, proton-permeable channels in two species of reef-building corals. We performed a characterization of their biophysical properties and found that these channels are fast-activating and modulated by the pH gradient in a manner that makes them interesting models for studying these processes more easily. We have also developed an allosteric gating model that provides mechanistic insight into the modulation of voltage-dependence by protons. This work also represents the first functional characterization of any ion channel in scleractinian corals. We discuss the implications of the presence of these channels in the membranes of coral cells in the calcification and pH regulation processes and possible consequences of ocean acidification related to the function of these channels.


2019 ◽  
Vol 51 (11) ◽  
pp. 735-740 ◽  
Author(s):  
Ke Xiao ◽  
Lingjia Yu ◽  
Lisi Zhu ◽  
Zhihong Wu ◽  
Xisheng Weng ◽  
...  

AbstractOsteoarthritis (OA) is a degenerative chronic disease affecting the whole joint structures. With the increment in life expectancy and aging population, OA has become one of the largest socioeconomic burdens, associated with pain and loss of joint function. However, early laboratory tests of OA are still lacking. Therefore, new diagnostic tests for this disease are urgently needed. In this study, to gain an insight into the pathogenesis and the potential biomarkers of OA, we implemented a comparative urine proteomics study on OA patients and health people using iTRAQ-based mass spectrometry technology. Western blotting was used to validate the relative changes in urine protein levels for four of the identified proteins. We constructed a comprehensive urine proteome profile of the OA patients and identified 102 proteins differently changed in abundance. Forty-six proteins were upregulated and 56 proteins were significantly downregulated in OA patients. Furthermore, the proteins, COL-4, MMP9, adiponectin, and BBOX1 were validated through Western blots, which can serve as valuable candidate biomarkers and help to illustrate the pathogenesis of OA. These findings may provide clues for promising biomarkers for the early diagnosis and also offer a theoretical basis for the early treatment of OA.


Author(s):  
Hanna Isaksson ◽  
Viktoria Prantner ◽  
Jukka S. Jurvelin

Fragility fractures due to degradation of the bone tissue during aging or development of osteoporosis are responsible for significant morbidity and mortality in elderly patients. A variety of factors contribute to the overall resistance of bones to fracture, e.g. the bone quality. Traditionally, bone mineral density (BMD) as assessed by the dual energy x-ray absorptiometry (DXA) is the gold standard for osteoporosis diagnostics 1. However, BMD alone is insufficient to explain fracture risk in patients 2. Additional characterization of bone structural parameters may provide more insight into the predictive capacity of BMD with respect to bone structural parameters. Further, as various skeletal sites are used to assess bone status, differences in structural characteristics of skeletal sites should be addressed.


Sign in / Sign up

Export Citation Format

Share Document