ABSTRACT
BACKGROUND: Type 2 diabetes mellitus (T2DM) is a complex, pandemic disease contributing towards the global burden of health issues. To date, there are no simple clinical tests for the early detection of T2DM. METHOD: To identify potential peptide biomarkers for such applications, 406 sera of T2DM patients (n = 206) and healthy controls (n = 200) are analyzed by using MALDI-TOF MS with a cross-sectional case-control design. RESULT: Six peptides (peaks m/z 1452.9, 1692.8, 1946.0, 2115.1, 2211.0 and 4053.6) are identified as candidate biomarkers for T2DM. A diagnostic model constructed with six peptides is able to discriminate T2DM patients from healthy controls, with an accuracy of 82.20%, sensitivity of 82.50%, and specificity of 77.80% in the validation set. Peptide peaks m/z 1452.9 and 1692.8 are identified as fragments of the complement C3f, while peptide peaks m/z 1946.0, 2115.1, and 2211.0 are identified as the fragments of kininogen 1 isoform 1 precursor. CONCLUSION: This study reinforces proteomic analyses as a potential technique for defining significant clinical peptide biomarkers, providing a simple and convenient diagnostic model for T2DM in clinical examination.
Subject(s)
Diabetes Mellitus, Type 2/blood , Proteomics , Biomarkers/blood , Cross-Sectional Studies , Diabetes Mellitus, Type 2/diagnosis , Female , Humans , Male , Middle Aged , Spectrometry, Mass, Matrix-Assisted Laser Desorption-IonizationABSTRACT
Three genes that encode MAP65-1 family proteins have been identified in the Nicotiana tabacum genome. In this study, NtMAP65-1c fusion protein was shown to bind and bundle microtubules (MTs). Further in vitro investigations demonstrated that NtMAP65-1c not only alters MT assembly and nucleation, but also exhibits high MT stabilizing activity against cold or katanin-induced destabilization. Analysis of NtMAP65-1c-GFP expressing BY-2 cells clearly demonstrated that NtMAP65-1c was able to bind to MTs during specific stages of the cell cycle. Furthermore, in vivo, NtMAP65-1c-GFP-bound cortical MTs displayed an increase in resistance against the MT-disrupting drug, propyzamide, as well as against cold temperatures. Taken together, these results strongly suggest that NtMAP65-1c stabilizes MTs and is involved in the regulation of MT organization and cellular dynamics.
Subject(s)
Microtubule-Associated Proteins/physiology , Microtubules/metabolism , Nicotiana/metabolism , Plant Proteins/physiology , Green Fluorescent Proteins/analysis , Microtubule-Associated Proteins/genetics , Microtubule-Associated Proteins/metabolism , Microtubules/ultrastructure , Plant Proteins/genetics , Plant Proteins/metabolism , Polymerization , Protein Stability , Recombinant Fusion Proteins/analysis , Nicotiana/ultrastructureABSTRACT
Nine genes that encode proteins of the MAP65 family have been identified in the Arabidopsis thaliana genome. In this study, we reported that AtMAP65-2, a member of the AtMAP65 family, could strongly stabilize microtubules (MTs). Bacterially-expressed AtMAP65-2 fusion proteins induced the formation of large MT bundles in vitro. Although AtMAP65-2 showed little effect on MT assembly or nucleation, AtMAP65-2 greatly stabilized MTs that were subjected to low-temperature treatment in vitro. Analyses of truncated versions of AtMAP65-2 indicated that the region that encompassed amino acids 495-578, which formed a flexible extended loop, played a crucial role in the stabilization of MTs. Analysis of suspension-cultured Arabidopsis cells that expressed the AtMAP65-2-GFP fusion protein showed that AtMAP65-2 co-localized with MTs throughout the cell cycle. Cortical MTs that were decorated with AtMAP65-2-GFP were more resistant to the MT-disrupting drug propyzamide and to ice treatment in vivo. The results of this study demonstrate that AtMAP65-2 strongly stabilizes MTs and is involved in the regulation of MT organization and dynamics.
