An Approach to Spatiotemporally Resolve Protein Interaction Networks in Living Cells - B2AR_DOR
Ontology highlight
ABSTRACT: SRM assays were generated for selected interactors of B2AR and DOR(MSV000084857), as well as for localization controls and ribosomal proteins (RPL18A, RPL28, RPL3, RPL35A, RPL6) as internal controls for normalization (Table S5 in publication). SRM assay generation was performed using Skyline. For all targeted proteins, proteotypic peptides and optimal transitions for identification and quantification were selected based on a spectral library generated from the shotgun MS experiments. The Skyline spectral library was used to extract optimal coordinates for the SRM assays, e.g., peptide fragments and peptide retention times. For each protein 1-4 peptides were selected based on intensity, peptide length as well as chromatographic performance. For each peptide the 4 best SRM transitions were selected based on intensity and peak shape. Digested peptide mixtures were analyzed by LC-SRM on a Thermo Scientific TSQ Quantiva MS system equipped with a Proxeon
Easy nLC 1200 ultra high-pressure liquid chromatography and autosampler system. Samples were injected onto a C18 column (25 cm x 75 mm I.D. packed with ReproSil Pur C18 AQ 1.9 mm particles) in 0.1% formic acid and then separated with an 80 min gradient from 5% to 40% Buffer B (90% ACN/10% water/0.1% formic acid) at a flow rate of 300 nl/min. SRM acquisition was performed operating Q1 and Q3 at 0.7 unit mass resolution. For each peptide the best 4 transitions were monitored in a scheduled fashion with a retention time window of 4 min and a cycle time fixed to 2s. Argon was used as the collision gas at a nominal pressure of 1.5 mTorr. Collision energies were calculated by, CE = 0.0348 * (m/z) + 0.4551 and CE = 0.0271 * (m/z) + 1.5910 (CE, collision en- ergy and m/z, mass to charge ratio) for doubly and triply charged precursor ions, respectively. RF lens voltages were calculated by, RF= 0.1088 * (m/z) + 21.029 and RF= 0.1157 * (m/z) + 0.1157 (RF, RF lens voltage andm/z, mass to charge ratio) for doubly and triply charged precursor ions, respectively. SRM data were processed using Skyline. Protein significance analysis for the different time points was performed using MSstats. Normalization across samples was conducted based on selected global standard proteins (RPL18A, RPL28, RPL3, RPL35A, RPL6). Each protein was tested for abundance differences comparing DOR-APEX2 time points to the spatial references, PM-APEX2 and ENDO-APEX2. Proteins with an adjusted p-value < 0.05 were considered significant.
INSTRUMENT(S): TSQ Quantiva
ORGANISM(S): Homo Sapiens (ncbitaxon:9606)
SUBMITTER: Ruth Huttenhain
PROVIDER: MSV000084966 | MassIVE | Mon Feb 17 18:50:00 GMT 2020
SECONDARY ACCESSION(S): PXD017570
REPOSITORIES: MassIVE
ACCESS DATA