cytolinker

Cyto linker, or cytolinker, refers to a class of proteins that connect cytoskeletal networks to each other and to cellular membranes and junctions. By tethering actin filaments, microtubules, and intermediate filaments to membranes and cell–cell junctions, cytolinkers help maintain cell shape, organize the cytoskeleton, and coordinate mechanical forces with signaling and trafficking.

Most cytolinkers are modular, with distinct domains for binding filaments and for interactions with membrane proteins or scaffolds. Notable families include the plakin family (for example plectin), which can connect all three cytoskeletal networks to desmosomes and hemidesmosomes; spectraplakins such as MACF1; desmosomal proteins such as desmoplakin that anchor intermediate filaments to cell junctions; and filamins that cross-link actin and link to transmembrane receptors. Dystrophin–glycoprotein complexes also function as cytolinkers in muscle.

Functions include mechanical resilience, spatial organization of networks, and facilitation of signaling pathways that regulate migration, polarity, and vesicle trafficking. They also contribute to organelle positioning and acceleration of responses to mechanical stress.

Mutations or dysregulation of cytolinkers are linked to disease. Plectin mutations cause epidermolysis bullosa with muscular dystrophy; desmosomal defects contribute to cardiomyopathies and skin diseases; disruptions in dystrophin–glycoprotein interactions underlie muscular dystrophy. Research continues to reveal how these proteins integrate structural and signaling roles in health and disease.

See also: cytoskeleton, plakins, desmosomes, hemidesmosomes, spectraplakins.