bioRxiv Science⌕ Search

Biology subjects

Carvalho, V.

Publications and source records attributed to Carvalho, V..

2 recordsLinked to original sources

Metabolomic profiling revels systemic signatures of premature aging induced by Hutchinson-Gilford Progeria Syndrome

Hutchinson-Gilford Progeria Syndrome (HGPS) is an extremely rare genetic disorder. HGPS children present a high incidence of cardiovascular complications along with altered metabolic processes and accelerated aging process. No metabolic biomarker is known and the mechanisms underlying premature aging are not fully understood. The present study analysed plasma from six HGPS patients of both sexes (7.7{+/-}1.4 years old; mean{+/-}SD) and eight controls (8.6{+/-}2.3 years old) by LC-MS/MS in high-resolution non-targeted metabolomics (Q-Exactive Plus). Several endogenous metabolites with statistical difference were found. Multivariate statistics analysis showed a clear separation between groups. Potential novel metabolic biomarkers are identified using the multivariate area under ROC curve (AUROC) based analysis, showing an AUC value higher than 0.80 using only two metabolites, and reaching 1.00 when increasing the number of metabolites in the AUROC model. Targeted metabolomics was used to validate some of the metabolites identified by the non-targeted method. Taken together, changed metabolic pathways in that panel involve sphingolipid, amino acid, and oxidation of fatty acids among others. In conclusion our data show significant alterations in cellular energy use and availability, in signal transduction, and in lipid metabolites, creating new insights on metabolic alterations associated with premature aging.

pathology↗

Large conformational changes in FtsH create an opening for substrate entry

AAA+ proteases are degradation machines, which exploit ATP hydrolysis to unfold protein substrates and translocate them through a central pore towards a degradation chamber. FtsH, a bacterial membrane-anchored AAA+ protease, plays a vital role in membrane protein quality control. Although cytoplasmic structures are described, the full-length structure of bacterial FtsH is unknown, and the route by which substrates reach the central pore remains unclear. We use electron microscopy to determine the 3D map of the full-length Aquifex aeolicus FtsH hexamer. Moreover, detergent solubilisation induces the formation of fully active FtsH dodecamers, which consist of two FtsH hexamers in a single detergent micelle. FtsH structures reveal that the cytosolic domain can tilt with respect to the membrane. A flexible linker of ~20 residues between the second transmembrane helix and the cytosolic domain permits the observed large tilting movements, thereby facilitating the entry of substrate proteins towards the central pore for translocation.

biophysics↗