The phosphorylation of proteins at tyrosine residues has long been recognized as an important regulatory component of signal transduction. This is a reversible process, involving both enzymes that phosphorylate proteins on tyrosine residues as well as a rapidly expanding family of protein tyrosine phosphatases. These latter enzymes bear little resemblance to either the protein serine and protein threonine phosphatases or to the acid and alkaline phosphatases. In most tissues, the major PTPase is a vanadate- and molybdate-sensitive protein. On the basis of sequence analysis, PTP1B (PTPase 1B) expressed in human placenta exhibits similarities both with the common leukocyte antigen (CD45) and with LAR, a homolog of the neural adhesion molecule (NCAM). PTP1B is synthesized as a 435 amino acid precursor protein which is cleaved to generate the active 321 amino acid enzyme.
Background References
暂无
Sequence Similarity
Belongs to the protein-tyrosine phosphatase family. Non-receptor class 1 subfamily.
Tissue Specificity
Expressed in keratinocytes (at protein level).
Post-translational Modification
Oxidized on Cys-215; the Cys-SOH formed in response to redox signaling reacts with the alpha-amido of the following residue to form a sulfenamide cross-link, triggering a conformational change that inhibits substrate binding and activity. The active site can be restored by reduction.; Ser-50 is the major site of phosphorylation as compared to Ser-242 and Ser-243. Activated by phosphorylation at Ser-50.; S-nitrosylation of Cys-215 inactivates the enzyme activity.; Sulfhydration at Cys-215 following endoplasmic reticulum stress inactivates the enzyme activity, promoting EIF2AK3/PERK activity.
Western blot analysis of PTP1B on recombinant protein lysate using anti-PTP1B antibody at 1/5,000 dilution.
ICC staining PTP1B in LOVO cells (green). The nuclear counter stain is DAPI (blue). Cells were fixed in paraformaldehyde, permeabilised with 0.25% Triton X100/PBS.
ICC staining PTP1B in Siha cells (green). The nuclear counter stain is DAPI (blue). Cells were fixed in paraformaldehyde, permeabilised with 0.25% Triton X100/PBS.
Immunohistochemical analysis of paraffin-embedded human colon cancer tissue using anti-PTP1B antibody. Counter stained with hematoxylin.
Immunohistochemical analysis of paraffin-embedded human placenta tissue using anti-PTP1B antibody. Counter stained with hematoxylin.
Immunohistochemical analysis of paraffin-embedded mouse fallopian tubes tissue using anti-PTP1B antibody. Counter stained with hematoxylin.
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