ITK

ITK is mainly located in T cells and is crucial for initiating the T cell receptor's signaling cascade. When the T cell receptor is activated, ITK moves to the cell membrane, gets phosphorylated by LCK kinase, and then phosphorylates itself to become fully active. Active ITK then phosphorylates PLCG1, which initiates lipase activity and the release of calcium ions from the endoplasmic reticulum into the cytoplasm. This triggers the activation of the T cell nuclear factor (NFAT), which travels to the nucleus to regulate gene transcription. ITK is vital for regulating the adaptive immune response, affecting the development and function of both conventional and unconventional NKT cells, as well as the development and effector functions of Th2 and Th17 cells. Studies in mice lacking ITK have shown they are less susceptible to asthma, underscoring ITK's significant role in immune regulation.