Proposition of a reference serum for the immunochemical assay of human serum proteins]

Sera of healthy students (from Academy of Paris) aged between 18 and 30 years were collected with a view to routine clinical testing. 50 samples each representing the pooled sera of 400 individuals were investigated by evaluating 7 proteins for each pooled sample. Calculations of standard deviations showed that there existed a significant reproductibility of less than 2% for the population as a whole. These pooled sera representing 20 000 individual blood samples are proposed as a standard of human serum proteins.     

Correlation of mechanical properties in bulk metallic glasses with ~（27）Al NMR characteristics

We report 27Al NMR and magnetic susceptibility measurements of Zr and ZrHf-based bulk metallic glasses (BMGs). 27Al NMR Knight shift shows that there exists a clear correlation between the local electronic properties at Al sites and mechanical properties. In addition,magnetic susceptibility measurements also provide clues on the influence of the electronic states,especially the strong influence of d-orbital characteristics on the mechanical properties of toughness and hardness.     

Five amino acids in three HLA proteins explain most of the association between MHC and seropositive rheumatoid arthritis

The genetic association of the major histocompatibility complex (MHC) to rheumatoid arthritis risk has commonly been attributed to alleles in HLA-DRB1. However, debate persists about the identity of the causal variants in HLA-DRB1 and the presence of independent effects elsewhere in the MHC. Using existing genome-wide SNP data in 5,018 individuals with seropositive rheumatoid arthritis (cases) and 14,974 unaffected controls, we imputed and tested classical alleles and amino acid polymorphisms in HLA-A, HLA-B, HLA-C, HLA-DPA1, HLA-DPB1, HLA-DQA1, HLA-DQB1 and HLA-DRB1, as well as 3,117 SNPs across the MHC. Conditional and haplotype analyses identified that three amino acid positions (11, 71 and 74) in HLA-DRβ1 and single-amino-acid polymorphisms in HLA-B (at position 9) and HLA-DPβ1 (at position 9), which are all located in peptide-binding grooves, almost completely explain the MHC association to rheumatoid arthritis risk. This study shows how imputation of functional variation from large reference panels can help fine map association signals in the MHC.     

Syndecan-4 promotes cytokinesis in a phosphorylation-dependent manner

During mitosis, cells detach, and the cell–matrix interactions become restricted. At the completion of cytokinesis, the two daughter cells are still connected transiently by an intercellular bridge (ICB), which is subjected to abscission, as the terminal step of cytokinesis. Cell adhesion to the matrix is mediated by syndecan-4 (SDC4) transmembrane heparan sulfate proteoglycan. Our present work demonstrated that SDC4 promotes cytokinesis in a phosphorylation-dependent manner in MCF-7 breast adenocarcinoma cells. The serine179-phosphorylation and the ectodomain shedding of SDC4 changed periodically in a cell cycle-dependent way reaching the maximum at G2/M phases. On the contrary, the phospho-resistant Ser179Ala mutant abrogated the shedding. The phosphorylated full-length and shed remnants enriched along the mitotic spindles, and subsequently in the ICBs, however, proper membrane insertion was necessary for midbody localization. Expression of phosphomimicking Ser179Glu SDC4 resulted in incomplete abscission, whereas expression of the phospho-resistant SDC4 led to giant, multinucleated cells.