Biological database · BEGINNER LESSON
STRING
STRING is a database used to study protein-protein association and interaction networks, and to support functional enrichment analyses for sequenced genomes. Its outputs are computational and depend on the data it contains.
What STRING is
STRING is a biological database focused on protein-protein association networks. In this setting, a protein is a molecule made by cells, and a protein-protein interaction is a case where two proteins are linked by evidence that they work together or are associated. STRING is used with sequenced genomes, meaning genomes whose DNA sequence has been determined, so researchers can examine interaction networks and functional enrichment analyses, which look for biological themes shared by a set of proteins.
[1] How can biological databases support the new UN ... - PMC [3] Learning the language of protein-protein interactions - PMC - NIH
What it measures or organizes
STRING organizes information about proteins and their associations rather than measuring a single physical quantity. Its curated data can include large numbers of experimental and predicted protein-protein interactions. In one cited use, the database was filtered to high-confidence interactions, showing that users can choose confidence thresholds to focus on stronger or more reliable links.
[2] Mechanism prediction of Wenjing Tongluo Powder for post ... [3] Learning the language of protein-protein interactions - PMC - NIH
How it is used
Researchers can import a protein list into STRING, choose a species such as Homo sapiens, and build a protein interaction network. The resulting network can be exported and analyzed in other software, such as Cytoscape, to find hub genes or hub proteins, which are highly connected nodes in a network. STRING is also used together with pathway tools such as Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes to help generate testable hypotheses about mechanism.
[2] Mechanism prediction of Wenjing Tongluo Powder for post ...
Mechanism and evidence
STRING does not prove a mechanism by itself. It combines evidence from databases and other sources to propose links between proteins, and these links can then be used to suggest biological pathways or functional groups. Because the database contains both physical and predicted interactions, its output is a model of relationships, not direct experimental proof of what will happen in a cell.
[2] Mechanism prediction of Wenjing Tongluo Powder for post ... [3] Learning the language of protein-protein interactions - PMC - NIH
Limitations
The main limits are data quality, database completeness, and the fact that many results are computational predictions. If the underlying databases are incomplete or inaccurate, STRING-based conclusions can be affected. Also, a predicted network should be treated as a hypothesis until experimental work confirms it, and results may change with species choice, confidence settings, or filtering rules.
[2] Mechanism prediction of Wenjing Tongluo Powder for post ... [3] Learning the language of protein-protein interactions - PMC - NIH
SEE THE IDEA
How STRING is used in a workflow
Start with proteins from a genome or experiment.
Find known, predicted, or curated protein-protein associations.
Display proteins as connected nodes and links.
Look for hubs, pathways, or functional enrichment.
A protein list is entered into STRING, STRING returns an interaction network, and the network is then analyzed for patterns.
STRING turns protein names into an interaction map that can suggest biological themes, but the map remains a prediction until tested.
TRY IT YOURSELF
Test your understanding
Choose an answer, then check the explanation.
PUT IT TOGETHER
Match each concept to its meaning
Drag a label onto its description, or select a label and then select a description. This also works with a keyboard.
4 pairs to match
Sources and further reading
This general lesson was generated from public source material. It explains a concept; it does not interpret a private paper or provide medical advice.