Rae, H. | Search bioRxiv

bioRxiv2024

RAPDOR: Using Jensen-Shannon Distance for the computational analysis of complex proteomics datasets

The computational analysis of large proteomics datasets, such as those from gradient profiling or spatially resolved proteomics, is often as crucial as the experimental design. We present RAPDOR, a tool for intuitive analyzing and visualizing such datasets, based on the Jensen-Shannon distance and subsequent analysis of similarities between replicates, applied to three datasets. First, we examined the in-gradient distribution profiles of protein complexes with or without RNase treatment (GradR) to identify the set of RNA-binding proteins (RBPs) in the cyanobacterium Synechocystis sp. PCC 6803. RBPs play pivotal regulatory and structural roles; although numerous RBPs have been identified, the complete set is unknown for any species. RAPDOR identified 80 potential RBPs, including ribosomal proteins, likely RNA-modifying enzymes, and several proteins not previously associated with RNA binding. High-ranking putative RBPs, such as the universal stress protein Sll1388, or the translation inhibitor LrtA/RaiA, were predicted by RAPDOR but not the TriPepSVM algorithm, indicating uncharacterized RBP domains. These data are available online at https://synecho-rapdor.biologie.uni-freiburg.de, providing a comprehensive resource for RNase-sensitive protein complexes in cyanobacteria. We then show by reanalyzing existing datasets, that RAPDOR is effective in examining the intracellular redistribution of proteins under stress conditions. RAPDOR is a generic, non-parametric tool for the intuitive and versatile analysis of highly complex data sets such as the study of protein distributions using fractionation protocols.

bioinformatics↗

bioRxiv2023

Estradiol regulates local synthesis of synaptic proteome via sex-specific mechanisms.

Estrogens, specifically 17{beta}-estradiol (estradiol), can modulate synaptic function by regulating the expression and localisation of synaptic proteins. However, the mechanisms underlying estradiols regulation of synaptic protein expression, and whether if they occur in a sex specific manner, is not well understood. In this study, using sex-specific hippocampal slice cultures and mixed-sex primary hippocampal neurons, we investigated whether local protein synthesis is required for estradiol- induced synaptic protein expression. Estradiol rapidly increased the rate of protein synthesis and the number of actively translating ribosomes along dendrites and near synapses in both male and female hippocampal neurons. Importantly, these effects occurred independently of gene transcription. Moreover, estradiol also increased the abundance of nascent proteins localised to synapses, independently of gene transcription. Specifically, estradiol increased the synaptic expression of GluN2B- containing N-methyl-D-aspartate receptors and PSD-95 in male and female hippocampus. Mechanistically, mTOR signalling was required for estradiol-induced increases in overall local protein synthesis only in male but not female hippocampus. Consistent with this, mTOR signalling mediated estradiol increases in GluN2B in male, but not female, hippocampus. Conversely, mTOR inhibition, blocked estradiol-induced increased PSD-95 expression in both male and female hippocampus. Collectively, these data suggest that the rapid modulation of local protein synthesis by estradiol is required for changes in the synaptic proteome in male and female hippocampus, and that the requirement of the mTOR signalling pathway in these effects occur in both a sex-specific and protein-dependent manner, with this signalling pathway have a greater role in male compared to female hippocampus.

neuroscience↗