proteininteraction

Protein interaction refers to the physical association between two or more protein molecules, which can be direct binding or part of a larger multiprotein complex. Interactions may be transient or stable and are essential for most cellular processes, including signal transduction, metabolic channeling, transcriptional regulation, and structural assembly. Protein–protein interactions (PPIs) often display specificity and affinity that depend on factors such as amino acid interfaces, post-translational modifications, cellular localization, and expression levels. Interactions can be modulated by cellular context, environmental signals, or developmental stage, leading to dynamic networks known as interactomes.

PPIs form the basis of protein interaction networks that coordinate cellular function. They can be characterized by their strength, duration, and regulatory inputs, and are influenced by subcellular compartmentalization and the presence of cofactors. Some PPIs are constitutive and stable, forming core components of molecular machines, while many are transient and condition-dependent, enabling rapid response to stimuli. Disruptions or aberrations in PPIs can contribute to disease and may serve as therapeutic targets.

A range of methods exists to detect and study PPIs. Experimental approaches include yeast two-hybrid assays, co-immunoprecipitation, affinity purification coupled to mass spectrometry, pull-down assays, cross-linking mass spectrometry, and biophysical techniques such as surface plasmon resonance and Förster resonance energy transfer. Computational predictions and integrative analyses use sequence co-evolution, structural modeling, and network data to infer interactions and reconstruct interactomes. Public resources such as STRING, BioGRID, IntAct, DIP, MINT, and IID curate PPI data for researchers.