Detection of antibodies directed to the N-terminal region of GAD is dependent on assay format and contributes to differences in the specificity of GAD autoantibody assays for type 1 diabetes

Autoantibodies to glutamate decarboxylase (GADA) are sensitive markers of islet autoimmunity and type 1 diabetes. They form the basis of robust prediction models and are widely used for recruitment of subjects at high risk of type 1 diabetes to prevention trials. However GADA are also found in many individuals at low risk of diabetes progression. To identify the sources of diabetes irrelevant GADA reactivity therefore, we analyzed data from the 2009 and 2010 Diabetes Autoantibody Standardization Program GADA workshop and found that binding of healthy control sera varied according to assay type. Characterization of control sera found positive by radiobinding assay, but negative by ELISA showed that many of these sera reacted to epitopes in the N-terminal region of the molecule. This finding prompted development of an N-terminally truncated GAD65 radiolabel, (35)S-GAD65(96-585), which improved the performance of most GADA radiobinding assays (RBAs) participating in an Islet Autoantibody Standardization Program GADA substudy. These detailed workshop comparisons have identified a source of disease-irrelevant signals in GADA RBAs and suggest that N-terminally truncated GAD labels will enable more specific measurement of GADA in type 1 diabetes

The molecular characterisation of type IIA calcium-ATPases in Arabidopsis thaliana

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN031324 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Ca2+ pumps and Ca2+ antiporters in plant development

Calcium (Ca2+) efflux transporters remove Ca2+ from the cytosol of the cell either by transporting it out of the cell across the plasma membrane or into internal organelles. These transporters, which include Ca2+-ATPases and Ca2+/H+ antiporters, have a critical role in preventing Ca2+ toxicity, maintaining cytosolic Ca2+ at a low resting level, and transferring Ca2+ to specific cellular locations where it is required. Many genes encoding plant Ca2+-ATPases and Ca2+/H+ antiporters have now been identified and characterised to elucidate their biochemical and genetic features. Furthermore, the use of gene knockouts has begun to provide evidence for an involvement of these Ca2+ transporters in Ca2+ signalling networks and in various aspects of plant development