Open AccessDefining the Caprin-1 Interactome in Unstressed and Stressed Conditions
Author(s) -
Lucas Vu,
Asmita Ghosh,
Chelsea Tran,
Walters Aji Tebung,
Hadjara Sidibé,
Krystine Garcia-Mansfield,
Victoria David-Dirgo,
Ritin Sharma,
Patrick Pirrotte,
Robert Bowser,
Christine Vande Velde
Publication year - 2021
Publication title -
journal of proteome research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.644
H-Index - 161
eISSN - 1535-3907
pISSN - 1535-3893
DOI - 10.1021/acs.jproteome.1c00016
Subject(s) - stress granule , interactome , proteome , biology , microbiology and biotechnology , ribosome , cytoplasm , ribonucleoprotein , stable isotope labeling by amino acids in cell culture , proteomics , rna binding protein , rna , translation (biology) , messenger rna , biochemistry , gene
Cytoplasmic stress granules (SGs) are dynamic foci containing translationally arrested mRNA and RNA-binding proteins (RBPs) that form in response to a variety of cellular stressors. It has been debated that SGs may evolve into cytoplasmic inclusions observed in many neurodegenerative diseases. Recent studies have examined the SG proteome by interrogating the interactome of G3BP1. However, it is widely accepted that multiple baits are required to capture the full SG proteome. To gain further insight into the SG proteome, we employed immunoprecipitation coupled with mass spectrometry of endogenous Caprin-1, an RBP implicated in mRNP granules. Overall, we identified 1543 proteins that interact with Caprin-1. Interactors under stressed conditions were primarily annotated to the ribosome, spliceosome, and RNA transport pathways. We validated four Caprin-1 interactors that localized to arsenite-induced SGs: ANKHD1, TALIN-1, GEMIN5, and SNRNP200. We also validated these stress-induced interactions in SH-SY5Y cells and further determined that SNRNP200 also associated with osmotic- and thermal-induced SGs. Finally, we identified SNRNP200 in cytoplasmic aggregates in amyotrophic lateral sclerosis (ALS) spinal cord and motor cortex. Collectively, our findings provide the first description of the Caprin-1 protein interactome, identify novel cytoplasmic SG components, and reveal a SG protein in cytoplasmic aggregates in ALS patient neurons. Proteomic data collected in this study are available via ProteomeXchange with identifier PXD023271.