Phosphorylation, the addition of a phosphate group to a molecule, is a vital post-translational modification that regulates protein function and cellular signalling. Phosphorylation occurs on various amino acid residues, including serine, threonine, and tyrosine. Phosphotyrosine is the phosphorylated form of the amino acid tyrosine. Tyrosine phosphorylation is a distinctive modification as it occurs less frequently than serine or threonine phosphorylation but carries significant functional implications. It is predominantly associated with receptor tyrosine kinases (RTKs), which play crucial initiating roles in transmitting extracellular signals to the cell's interior. A key feature of phosphotyrosine is its ability to serve as a docking site for specific signalling proteins that contain Src Homology 2 (SH2) domains. The SH2 domains recognize and bind to phosphorylated tyrosine residues in a sequence-specific manner, enabling the recruitment of downstream signalling molecules to the activated receptor complex. This protein-protein interaction allows for the formation of dynamic signalling complexes, facilitating the transduction of extracellular signals to intracellular effectors. Phosphotyrosine-based signalling cascades are essential for a wide range of cellular processes. Activation of RTKs by ligand binding induces autophosphorylation of specific tyrosine residues within the receptor itself with the phosphorylated tyrosines then acting as docking sites for proteins involved in diverse signalling pathways. Phosphotyrosine-mediated signalling is therefore implicated in multiple processes such as cell growth, differentiation, survival, proliferation, migration, and metabolism. For example, the phosphotyrosine-mediated activation of the Ras-MAPK (Mitogen-Activated Protein Kinase) pathway is critical for cell proliferation and survival in response to growth factors. The phosphorylation of tyrosine residues on RTKs initiates a series of downstream phosphorylation events, leading to the activation of kinases, transcription factors, and other signalling molecules involved in cell growth and division. For example, tyrosine phosphorylation events can lead to the activation of small GTPases, such as Rac or Rho, which regulate cellular processes involving actin rearrangements such as cell migration or cell-cell adhesion. Phosphotyrosine-based signalling events are also crucial in immune cell signalling and antigen receptor signalling. In immune cells, the phosphorylation of tyrosine residues on immune receptors, such as T-cell receptors (TCRs) and B-cell receptors (BCRs), triggers downstream signalling events that culminate in immune responses, including the activation and development of immune cells. Finally, crosstalk between different RTKs and other receptor systems allows for the integration and coordination of multiple signals, enabling more complex cellular responses. Phosphotyrosine-mediated interactions between such receptors can lead to the activation of synergistic or antagonistic signalling pathways, adding additional complexity and regulation to cellular signalling networks. We provide a large product catalogue of research tools for investigating phospho Tyr, including STAP2 antibodies. Explore our full phospho Tyr product range below and discover more, for less.