mucinbinding

Mucin-binding refers to the interaction between proteins or protein domains and mucins, the high-molecular-weight glycoproteins that form mucus on epithelial surfaces. Mucins, such as MUC1, MUC2, and MUC5B, are characterized by extensive O-linked glycosylation, producing a dense mesh that protects and lubricates mucosal tissues. Binding to mucins can be mediated by specialized protein modules known as mucin-binding protein (MucBP) domains, or by lectin-like carbohydrate recognition domains that recognize specific glycan structures on mucin glycans.

A well-described class of mucin-binding entities is the mucin-binding protein (MucBP) domain, found in various Gram-positive bacteria. Proteins containing MucBP or similar mucin-binding motifs are commonly displayed on the cell surface, enabling direct contact with mucins.

In bacteria, mucin-binding promotes adhesion to mucus-rich surfaces, which can facilitate colonization, persistence, and, in some cases, invasion or biofilm formation on mucosal tissues. The interaction is influenced by the heterogeneity of mucin glycosylation, including sialylation and fucosylation patterns, which can modulate binding affinity and specificity. In nonpathogenic contexts, mucin-binding can support symbiotic colonization by commensals and probiotics, whereas in pathogens it can contribute to tropism for the gastrointestinal, respiratory, or reproductive tracts.

Research approaches to mucin-binding include in vitro binding assays with purified mucins or synthetic glycans, mutational analyses of mucin-binding proteins to define critical residues or domains, and structural studies to reveal the molecular basis of recognition. Understanding mucin-binding informs aspects of host–microbe interactions, mucosal immunity, and the development of strategies to influence microbial adhesion in health and disease.