BD Transduction Laboratories™ Protein Tyrosine Phosphatase (PTP) Sampler Kit

Protein tyrosine phosphatases (PTPs) regulate Tyr phosphorylation during cellular events such as proliferation, cell signaling, and oncogenic transformation. PTPs have at least one Tyr phosphatase domain containing an 11-residue sequence motif in which Arg and Cys residues are required for catalytic activtiy. This family can be subdivided into two groups, receptor and non-receptor PTPs. The receptor PTPs are transmembrane proteins with two phosphatase domains in the intracellular region and a variety of motifs in the extracellular region. Some receptor PTPs (CD45, RPTPα and RPTPβ) are heavily glycosylated in their extracellular domain. RPTPα and RPTPβ are expressed in the nervous system where they are important for initiation of signaling that regulates Tyr phosphorylation. CD45 dephosphorylates both lck and fyn in T cells and has been implicated in antigen receptor-induced responses in both T and B cells. LAR, another receptor PTP, contains three Ig-like and eight fibronectin type III-like domains similar to some neuronal cell adhesion molecules. These extracellular domains of LAR may promote cell-cell interactions that activate phosphatase domains important for axon pathfinding. Non-receptor PTPs, such as PTP1B, C, and D, contain SH2 domains for interaction with phosphotyrosine residues on Tyr receptor-like proteins, such as SHPS-1 and SIRPα1. SHPS-1 and SIRPα1 recruit phosphatases that regulate signal transduction pathways activated by growth factors, cytokines, or cell adhesion molecules. Other non-receptor PTPs such as KAP, VHR, and MKP2 may dephosphorylate cyclin dependent kinases or MAP kinases. Thus, PTPs function in the regulation of Tyr phosphorylation of proteins found in a diverse array of signaling pathways.