Tyrosine-protein phosphatase non-receptor type 1 also known as protein-tyrosine phosphatase 1B (PTP1B) is an enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 that is the founding member of the protein tyrosine phosphatase

Protein tyrosine phosphatase

Protein tyrosine phosphatases are a group of enzymes that remove phosphate groups from phosphorylated tyrosine residues on proteins. Protein tyrosine phosphorylation is a common post-translational modification that can create novel recognition motifs for protein interactions and cellular...

 (PTP) family. In humans it is encoded by the PTPN1 gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

. PTP1B is a negative regulator of the insulin signaling pathway and is considered a promising potential therapeutic target, in particular for treatment of type 2 diabetes.

Function

PTP1B was first isolated from a human placental protein extract, but it is expressed in many tissues. PTP1B is localized to the cytoplasmic face of the endoplasmic reticulum

Endoplasmic reticulum

The endoplasmic reticulum is an organelle of cells in eukaryotic organisms that forms an interconnected network of tubules, vesicles, and cisternae...

. PTP1B can dephosphorylate the phosphotyrosine residues of the activated insulin receptor

Insulin receptor

In molecular biology, the insulin receptor is a transmembrane receptor that is activated by insulin. It belongs to the large class of tyrosine kinase receptors....

 kinase. In mice, genetic ablation of PTPN1 results in enhanced insulin sensitivity. Several other tyrosine kinases, including epidermal growth factor receptor

Epidermal growth factor receptor

The epidermal growth factor receptor is the cell-surface receptor for members of the epidermal growth factor family of extracellular protein ligands...

, insulin-like growth factor 1 receptor, colony stimulating factor 1 receptor

Colony stimulating factor 1 receptor

Colony stimulating factor 1 receptor , also known as macrophage colony-stimulating factor receptor , and CD115 , is a cell-surface protein encoded, in humans, by the CSF1R gene...

, c-Src

Src (gene)

Proto-oncogene tyrosine-protein kinase Src is an enzyme that in humans is encoded by the SRC gene.Src is a proto-oncogene encoding a tyrosine kinase originally discovered by J. Michael Bishop and Harold E. Varmus, for which they won the 1989 Nobel Prize in Physiology or Medicine. It belongs to a...

, Janus kinase 2

Janus kinase 2

Janus kinase 2 is a human protein that has been implicated in signaling by members of the type II cytokine receptor family , the GM-CSF receptor family , the gp130 receptor family , and the single chain receptors...

, TYK2, and focal adhesion kinase as well as other tyrosine-phosphorylated proteins, including STAT5

STAT5

STAT5 refers to two highly related proteins, STAT5A and STAT5B, which are encoded by separate genes, but are 90% identical at the amino acid level....

, BCAR1

BCAR1

Breast cancer anti-estrogen resistance protein 1 is a protein that in humans is encoded by the BCAR1 gene.-External links:* Info with links in the...

, DOK1

DOK1

Docking protein 1 is a protein that in humans is encoded by the DOK1 gene.-Interactions:DOK1 has been shown to interact with RET proto-oncogene, SH2D1A, LYN, RAS p21 protein activator 1, INPP5D, CD117, SHC1, Abl gene and TEC.-Further reading:...

, beta-catenin

Beta-catenin

Beta-catenin is a protein that in humans is encoded by the CTNNB1 gene. In Drosophila, the homologous protein is called armadillo...

 and cortactin

Cortactin

Cortactin is a monomeric protein located in the cytoplasm of cells that can be activated by external stimuli to promote polymerization and rearrangement of the actin cytoskeleton, especially the actin cortex around the cellular periphery. It is present in all cell types...

 have also been described as PTP1B substrates.

Interactions

PTPN1 has been shown to interact

Protein-protein interaction

Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...

 with BCAR1

BCAR1

Breast cancer anti-estrogen resistance protein 1 is a protein that in humans is encoded by the BCAR1 gene.-External links:* Info with links in the...

, epidermal growth factor receptor

Epidermal growth factor receptor

The epidermal growth factor receptor is the cell-surface receptor for members of the epidermal growth factor family of extracellular protein ligands...

, Grb2

Grb2

Growth factor receptor-bound protein 2 also known as Grb2 is an adaptor protein involved in signal transduction/cell communication. In humans, the GRB2 protein is encoded by the GRB2 gene....

 and IRS1

IRS1

Insulin receptor substrate 1 is a protein that in humans is encoded by the IRS-1 gene.-Function:Insulin receptor substrate 1 plays a key role in transmitting signals from the insulin and insulin-like growth factor-1 receptors to intracellular pathways PI3K / Akt and Erk MAP kinase...

.