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Bronshtein, I.

Publications and source records attributed to Bronshtein, I..

2 recordsLinked to original sources

Unifying the analysis of bottom-up proteomics data with CHIMERYS

Proteomic workflows generate vastly complex peptide mixtures that are analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), creating thousands of spectra, most of which are chimeric and contain fragment ions from more than one peptide. Because of differences in data acquisition strategies such as data-dependent (DDA), data-independent (DIA) or parallel reaction monitoring (PRM), separate software packages employing different analysis concepts are used for peptide identification and quantification, even though the underlying information is principally the same. Here, we introduce CHIMERYS, a novel, spectrum-centric search algorithm designed for the deconvolution of chimeric spectra that unifies proteomic data analysis. Using accurate predictions of peptide retention time, fragment ion intensities and applying regularized linear regression, it explains as much fragment ion intensity as possible with as few peptides as possible. Together with rigorous false discovery rate control, CHIMERYS accurately identifies and quantifies multiple peptides per tandem mass spectrum in DDA, DIA and PRM experiments.

biochemistry↗

LAP2alpha maintains a mobile and low assembly state of A-type lamins in the nuclear interior

Lamins form stable filaments at the nuclear periphery in metazoans. Unlike B-type lamins, lamins A and C localize also in the nuclear interior, where they interact with lamin-associated polypeptide 2 alpha (LAP2). We show that lamin A in the nuclear interior is formed from newly expressed pre-lamin A during processing and from soluble mitotic mature lamins in a LAP2-independent manner. Binding of LAP2 to lamins A/C in the nuclear interior during interphase inhibits formation of higher order structures of lamin A/C in vitro and in vivo, keeping lamin A/C in a mobile low assembly state independent of lamin A/C S22 phosphorylation. Loss of LAP2 causes formation of larger, less mobile and biochemically stable lamin A/C structures in the nuclear interior, which reduce the mobility of chromatin. We propose that LAP2 is essential to maintain a mobile lamin A/C pool in the nuclear interior, which is required for proper nuclear functions.

cell biology↗