P43403, P43405

The Syk family protein tyrosine kinase Zap-70 is expressed in T and NK cells and plays a critical role in mediating T cell activation in response to T cell receptor (TCR) engagement. Zap-70 is recruited to the receptor complex, where phosphorylation activates downstream signaling pathways that lead to T cell activation, proliferation, and differentiation. This process is vital for the adaptive immune response, enabling T cells to effectively respond to pathogens and maintain immune homeostasis. Zap-70′s importance is underscored by its association with severe immunodeficiency when mutated, highlighting an essential role in T cell function.