An Update on MRMAssayDB: A Comprehensive Resource for Targeted Proteomics Assays in the Community

Precise multiplexed
quantification of proteins in biological samples
can be achieved by targeted proteomics using multiple or parallel
reaction monitoring (MRM/PRM). Combined with internal standards, the
method achieves very good repeatability and reproducibility enabling
excellent protein quantification and allowing longitudinal and cohort
studies. A laborious part of performing such experiments lies in the
preparation steps dedicated to the development and validation of individual
protein assays. Several public repositories host information on targeted
proteomics assays, including NCI’s Clinical Proteomic Tumor
Analysis Consortium assay portals, PeptideAtlas SRM Experiment Library,
SRMAtlas, PanoramaWeb, and PeptideTracker, with all offering varying
levels of details. We introduced MRMAssayDB in 2018 as an integrated
resource for targeted proteomics assays. The Web-based application
maps and links the assays from the repositories, includes comprehensive
up-to-date protein and sequence annotations, and provides multiple
visualization options on the peptide and protein level. We have extended
MRMAssayDB with more assays and extensive annotations. Currently it
contains >828 000 assays covering >51 000 proteins
from
94 organisms, of which >17 000 proteins are present in >2400
biological pathways, and >48 000 mapping to >21 000
Gene Ontology terms. This is an increase of about four times the number
of assays since introduction. We have expanded annotations of interaction,
biological pathways, and disease associations. A newly added visualization
module for coupled molecular structural annotation browsing allows
the user to interactively examine peptide sequence and any known PTMs
and disease mutations, and map all to available protein 3D structures.
Because of its integrative approach, MRMAssayDB enables a holistic
view of suitable proteotypic peptides and commonly used transitions
in empirical data. Availability: http://mrmassaydb.proteincentre.com.