Structural Biochemistry/Transforming Growth Factor Beta/Cytokine

Cytokines are protein molecules, generally small, that are responsible for a variety of cell-signaling and transducing functions. These molecules vary in form and function, and the term cytokine broadly covers molecules produced by all types of cells in the body. Each cytokine has a corresponding receptor, which enables the expression of the protein and can result in up-regulation or down-regulation of other mediating agents.