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Session Length
~17 min
Adaptive Checks
15 questions
Transfer Probes
8
Proteomics is the large-scale study of the entire set of proteins produced or modified by an organism, tissue, or cell at a given time. While the genome of an organism is relatively static, the proteome is highly dynamic, changing in response to developmental stage, environmental conditions, disease states, and cellular signaling. Because proteins are the primary functional molecules in cells, responsible for catalyzing reactions, providing structural support, transmitting signals, and regulating gene expression, understanding the proteome is essential for a complete picture of biological processes.
The field emerged in the mid-1990s, enabled by advances in mass spectrometry, two-dimensional gel electrophoresis, and bioinformatics. Modern proteomics employs shotgun approaches using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), which can identify and quantify thousands of proteins in a single experiment. Techniques such as isobaric tagging (TMT, iTRAQ), label-free quantification, and data-independent acquisition (DIA) have dramatically increased throughput and reproducibility. Structural proteomics, interaction proteomics, and post-translational modification (PTM) analysis represent specialized branches that address protein folding, protein-protein interaction networks, and chemical modifications like phosphorylation, ubiquitination, and glycosylation.
Proteomics has profound applications in biomedicine, agriculture, and biotechnology. In clinical settings, proteomic profiling is used for biomarker discovery, drug target identification, and personalized medicine. Cancer proteomics, for example, has identified diagnostic markers and therapeutic targets that have led to new treatment strategies. The integration of proteomics with genomics, transcriptomics, and metabolomics within a systems biology framework provides a multi-omics view of cellular function, enabling researchers to model complex biological networks and understand disease mechanisms at an unprecedented level of detail.
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An analytical technique that measures the mass-to-charge ratio of ions to identify and quantify molecules. In proteomics, tandem mass spectrometry (MS/MS) fragments peptides and matches their spectra to protein databases for identification.
Example: A researcher uses LC-MS/MS to analyze a tumor biopsy, identifying over 5,000 proteins and detecting elevated levels of HER2, confirming the cancer subtype.
A protein separation technique that resolves proteins in two steps: first by isoelectric point (charge) and then by molecular weight, producing a map of spots where each spot represents one or more protein species.
Example: Comparing 2-DE gels from healthy and diseased liver tissue reveals several spots that are present only in the disease state, flagging candidate biomarker proteins.
Chemical modifications that occur on proteins after translation, such as phosphorylation, glycosylation, acetylation, and ubiquitination. PTMs regulate protein activity, localization, interactions, and degradation.
Example: Phosphoproteomics reveals that a kinase inhibitor drug reduces phosphorylation of EGFR at tyrosine 1068, confirming on-target activity in cancer cells.
Physical contacts between two or more proteins that occur through molecular recognition. Mapping PPI networks reveals how proteins collaborate in signaling pathways, complexes, and cellular processes.
Example: Affinity purification coupled with mass spectrometry (AP-MS) identifies that the tumor suppressor p53 interacts with MDM2, informing drug design to disrupt this interaction in cancer therapy.
A bottom-up approach in which a complex protein mixture is enzymatically digested into peptides, separated by liquid chromatography, and analyzed by tandem mass spectrometry without prior protein-level separation.
Example: A cell lysate is digested with trypsin, and the resulting peptide mixture is analyzed by LC-MS/MS, identifying 8,000 proteins in a single four-hour run.
Methods for measuring relative or absolute protein abundance across samples. Approaches include label-free quantification, metabolic labeling (SILAC), and chemical labeling (TMT, iTRAQ).
Example: Using TMT 16-plex labeling, researchers compare protein expression across 16 patient samples simultaneously, identifying 200 proteins significantly upregulated in responders to immunotherapy.
The entire complement of proteins expressed by a genome, cell, tissue, or organism at a specific time and under specific conditions. Unlike the genome, the proteome is dynamic and context-dependent.
Example: The human proteome is estimated to include over 20,000 protein-coding genes, but alternative splicing and PTMs expand the functional proteome to hundreds of thousands of distinct proteoforms.
The process of identifying measurable biological indicators (proteins, peptides, or PTMs) that correlate with a disease state, prognosis, or treatment response, typically using comparative proteomic analysis.
Example: Proteomic analysis of blood plasma identifies elevated levels of prostate-specific antigen (PSA) and a panel of complementary protein markers that improve early detection of prostate cancer.
More terms are available in the glossary.
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