Protein Tyrosine Phosphatase

Protein Tyrosine Phosphatase Receptor Type C, also known as PTPRC, which is a vital regulator of T- and B-cell antigen receptor signaling, is also a part of the protein tyrosine phosphatase (PTP) family. PTPs are signaling molecules which regulate a variety of cellular processes including differentiation, cell growth, mitosis, and oncogenic transformation. PTPRC contains an extracellular domain, a single transmembrane segment and 2 tandem intracytoplasmic catalytic domains, and therefore is classified as a receptor type PTP.

PTPN7 performs specifically on tyrosine-phosphorylated MAPK1. PTPN7 takes part in the regulation of signal transduction and T and B-lymphocyte development.

PTPN6 is a member of the protein tyrosine phosphatase (PTP) family. PTPs are known to be signaling molecules that regulate a variety of cellular processes including cell growth, differentiation, mitotic cycle, and oncogenic transformation. N-terminal part of this PTP contains two tandem Src homolog (SH2) domains, which act as protein phospho-tyrosine binding domains, and mediate the interaction of this PTP with its substrates. This PTP is expressed primarily in hematopoietic cells, and functions as an important regulator of multiple signaling pathways in hematopoietic cells. This PTP has been shown to interact with, and dephosphorylate a wide spectrum of phospho-proteins involved in hematopoietic cell signaling. Multiple alternatively spliced variants of this gene, which encode distinct isoforms, have been reported.

Protein Tyrosine Phosphatase Non Receptor Type-4, also known asPTPN4 belongs to the protein tyrosine phosphatase, PTP family. PTPs are identified as signaling molecules which regulate a variety of cellular processes as well as cell growth, differentiation, mitotic cycle, and oncogenic transformation. PTPN4 is broadly expressed non-receptor protein tyrosine phosphatase. In addition, PTPN4 interacts with glutamate receptor delta 2 & epsilon, and affects glutamate receptors signaling and/or in regulation of their activities through tyrosine dephosphorylation.

Astyrosine-protein phosphatase non-receptor type 11 isoform 2 (PTPN11), is a member of the protein-tyrosine phosphatase family, non-receptor class 2 subfamily. PTPN11 takes part in signal transduction from the cell surface to the nucleus downstream of various cytosolic protein tyrosine kinases as well as receptors. PTPN11 deficient cells have poor mobility due to excessive phosphorylation of FAK as well as other proteins which interfere with the rotation of cell attachment points in the focal adhesion complex.

Protein Tyrosine Phosphatase 1B is the founding member of the protein tyrosine phosphatase (PTP) family, which was isolated and identified based on its enzymatic activity and amino acid sequence. PTPs catalyze the hydrolysis of the phosphate monoesters specifically on tyrosine residues. Members of the PTP family share a highly conserved catalytic motif, which is essential for the catalytic activity. PTPs are known to be signaling molecules that regulate a variety of cellular processes including cell growth, differentiation, mitotic cycle, and oncogenic transformation. This PTP has been shown to act as a negative regulator of INS signaling by dephosphorylating the phosphotryosine residues of INS receptor kinase. This PTP was also reported to dephosphorylate epidermal growth factor receptor kinase, as well as JAK2 and TYK2 kinases, which implicated the role of this PTP in cell growth control, and cell response to IFN stimulation.

Protein tyrosine phosphatase mitochondrial 1 (PTPMT1) is a broadly expressed PTP membrane protein with high expression levels in pancreatic beta cells. The PTPMT1 protein is completely restricted to the matrix face of the inner membrane of the mitochondrion. PTPMT1 is responsible for dephosphorylating mitochondrial proteins and thus has a major role in the production of ATP. PTPMT1 exhibits a specific preference for the lipid signaling molecule phosphatidylinositol 5-phosphate as substrate.

Protein Tyrosine Phosphatase Type IVA Member 3 (PTP4A3) is a member of a small class of prenylated protein tyrosine phosphatases (PTPs) which remove phosphate modifications from tyrosine residues on proteins. PTP4A3 enhances cell proliferation, cell motility and invasive activity. PTP4A3 functions as a protein tyrosine phosphatase which stimulates progression from G1 into S phase during mitosis. PTP4A3 is mostly expressed in cardiomyocytes and skeletal muscle; it is also found in the pancreas.
PTP4A3 is always overexpressed in colon cancer metastasis. PTP4A3 is notably overexpressed in liver metastasis of colorectal cancer. High levels of PTP4A3 expression are linked to tumorigenesis and metastasis; therefore it is overexpressed in metastatic colorectal, ovarian, liver and skin cancers. PTP4A3 may be involved in the progression of cardiac hypertrophy by inhibiting intracellular calcium mobilization in response to angiotensin II. PTP4A3 is inhibited by sodium orthovanadate and peroxovanadium compounds.

PTP4A2 is part of a small class of the protein tyrosine phosphatase (PTP) family. PTP4A2 is localized to the early endosome that take part in a variety of cellular activities. PTP4A2 protein interacts with the beta-subunit of Rab geranylgeranyltransferase II (beta GGT II), therefore has a role as a regulator of GGT II activity. Overexpression of PTP4A2 in mammalian cells conferred a transformed phenotype, which suggested its role in tumorigenesis.

Protein tyrosine phosphatase type IVA 1 (PTP4A1) is a cell signaling molecule that has regulatory roles in a variety of cellular processes. PTP4A1 is a unique nuclear PTP which is induced in regenerating liver and mitogen stimulated cells. PTP4A1 is primarily expressed in the spleen, bone marrow, thymus, lymph nodes, T lymphocytes and tonsil and is overexpressed in tumor cell lines.