Control of T cell function by positive and negative regulators.

T cells are an essential element of the body's immune system. Engagement of the T cell receptor is responsible for initiating the signaling events that can activate, inactivate, or eliminate T cells, depending on the magnitude and duration of the signal. Control of T cell signaling occurs through both positive and negative regulation, as well as through the actions of molecular scaffolds that contribute to the formation of signaling complexes. The T Cell Signal Transduction Pathway at the STKE Connections Maps highlights the molecular components that are responsible for T cell activation. Understanding the mechanisms that regulate T cell responsiveness will aid in the development of therapeutic agents to treat infection, cancer, and autoimmune disease and immune deficiency.