PTP1B Mouse, Unlabeled, Clone: 15, BD

PTP1B is a member of the class of enzymes termed protein tyrosine phosphatases(PTPs). This 50 kDa protein contains a conserved phosphatases domain at residues 30-278 and is localized to the cytoplasmic face of the endoplasmic reticulum by its C-terminal 35 residues. Its interactions with other proteins are mediated by proline-rich regions and SH2 compatible sequences. PTP1B is thought to act as a negative regulator in insulin signaling. Insulin stimulation induces its association with the insulin receptor and tyrosine phosphorylation. Its overexpression inhibits proximal and distal insulin signaling events, possibly due to receptor dephosphorylation. Microinjection of PTP1B into Xenopus oocytes blocks insulin-induced maturation. Additional studies demonstrate that PTP1B undergoes cell cycle-dependent and/or stress-induced serine phosphorylation. This suggests further regulatory roles that are not yet defined.