Several analogues of somatostatin were examined in the Mia PaCa-2 human pancreatic cancer cell line for their ability to promote tyrosine phosphatase activity affecting the receptors for the epidermal growth factor. The inhibition of growth of the Mia PaCa-2 cells in culture was also evaluated to determine the mechanism of action of somatostatin analogues and their relative effectiveness in inh...

Eyes Absents (EYA) are multifunctional proteins best known for their role in organogenesis. There is accumulating evidence that overexpression of EYAs in breast and ovarian cancers, and in malignant peripheral nerve sheath tumors, correlates with tumor growth and increased metastasis. The EYA protein is both a transcriptional activator and a tyrosine phosphatase, and the tyrosine phosphatase ac...

The effects of somatostatin analogues RC-160 and SMS-201-995 on tyrosine phosphatase and cell proliferation were investigated in COS-7 and NIH 3T3 cells expressing human somatostatin receptor subtype 1 or 2 (SSTR1 or SSTR2). Binding experiments were performed on membranes from COS-7 cells expressing human SSTR1 or SSTR2 using 125I-labeled [Tyr11]S-14 or [Tyr3]SMS-201-995, respectively. The soma...

YopH is a protein tyrosine phosphatase and an essential virulence determinant of the pathogenic bacterium Yersinia. Yersinia delivers YopH into infected host cells using a type III secretion mechanism. YopH dephosphorylates several focal adhesion proteins including p130Cas in human epithelial cells, resulting in disruption of focal adhesions and cell detachment from the extracellular matrix. Ho...

In the vascular system, synthesis of the potent vasodilator nitric oxide (NO) is tightly regulated by the constitutively expressed endothelial NO synthase (eNOS). Activity of eNOS is controlled by Ca2+/calmodulin and various seryl/threonyl protein kinases. Less is known about the importance of phosphorylation and dephosphorylation of tyrosyl residues. Therefore the role of tyrosine phosphatase ...

3,4-Dibromo-5-(2-bromo-3,4-dihydroxy-6-(isopropoxymethyl)benzyl)benzene-1,2-diol (HPN) is a synthetic analogue of 3,4-dibromo-5-(2-bromo-3,4-dihydroxy-6-(ethoxymethyl)benzyl)benzene-1,2-diol (BPN), which is isolated from marine red alga Rhodomela confervoides with potent protein tyrosine phosphatase 1B (PTP1B) inhibition (IC(50) = 0.84 μmol/L). The in vitro assay showed that HPN exhibited enhan...

Protein tyrosine phosphatases act in conjunction with protein kinases to regulate the tyrosine phosphorylation events that control cell activation and differentiation. We have isolated a previously undescribed human phosphatase, Lyp, that encodes an intracellular 105-kD protein containing a single tyrosine phosphatase catalytic domain. The noncatalytic domain contains four proline-rich potentia...

BACKGROUND Protein tyrosine phosphatase non-receptor type 1 is a therapeutic target for the type 2 diabetes mellitus. According to the International Diabetes Federation 2015 report, one out of 11 adults suffers from diabetes mellitus globally. OBJECTIVE Current anti-diabetic drugs can cause life-threatening side-effects. The present study proposes a pipeline for the development of effective a...

Evidence is presented showing that a protein tyrosine phosphatase different from CD45 is present on the membrane of human hematopoietic cells. The molecule recognized by the monoclonal antibody 143-41, which has been classified as CD148 in the VI International Workshop on Leukocyte Differentiation Antigens, was immunopurified and sequenced. The sequence obtained from N-terminus as well as from ...