OBJECTIVETo explore the hemolytic mechanism of glucose-6-phosphate dehydrogenase (G6PD) deficient erythrocytes in the view of phosphorylation of membrane protein.

METHODSThe alternation of membrane protein phosphorylation and the effect of dithiothreitol (DTT) on protein phosphorylation were analysed by Western blot technique. The activity of phosphotyrosine phosphatase (PTPs) was determined by using p-nitrophenyl phosphate as substrate.

RESULTSTyrosine phosphorylation of band 3 protein was obviously enhanced in G6PD-deficient erythrocytes. The activity of PTPs was low compared to the normal erythrocytes. The level of phosphotyrosine in G6PD-deficient erythrocytes incubated with DTT was almost the same as in those without DTT. The results were consistent with the activity of PTPs.

CONCLUSIONSPTPs activity reduction and tyrosine phosphorylation enhancement induced by oxidation in G6PD deficiency play an important role in erythrocytes hemolysis. However, the alternation of thiol group is not the only factor affecting the activity of PTPs in G6PD-deficient erythrocytes.

Anion Exchange Protein 1, Erythrocyte ; metabolism ; Blotting, Western ; Erythrocyte Membrane ; metabolism ; Glucosephosphate Dehydrogenase Deficiency ; enzymology ; metabolism ; Humans ; Phosphorylation ; Protein Tyrosine Phosphatases ; metabolism ; Tyrosine ; metabolism

OBJECTIVETo explore the expression of tyrosine phosphatase containing C-src homology SH-2 (SHP-1 and SHP-2) in benign prostate hyperplasia.

METHODSWith En Vision two-step method, the expression of SHP-1 and SHP-2 was detected in 10 cases of normal prostate tissue, 30 cases of BPH, 20 cases of PIN, 20 cases of high differential Pca and 20 cases of low differential Pca.

RESULTThe expression of SHP-2 in normal group was mainly distributed in the cytoplasm of secretive cells and basal cells, and a little part in the nucleu. In BPH it was distributed equally in the plasm and nucleu. In PIN, high differential Pca and low differential Pca, SHP-2 expressed mainly in nucleu. The average dyeing index of SHP-2 in each group is 0.4, 1.7, 2.1, 2.2 and 2.6. SHP-1 positive expression in normal prostate, BPH, PIN and high differential Pca showed differentiating layer staining in the cytoplasm of secretive cells and basal cells, while not in low differential Pca. The average dyeing index of SHP-1 in each group is 1.8, 1.8, 1.5, 1.2 and 0.4.

CONCLUSIONThere are transformation in signal transduction relation with SHP-1 and SHP-2 in the progress of prostate cell proliferation, differentiation and malignant. The abnormal activation and distribution of SHP-2 might induce prostate reconstruction and hyperplasia, even carcinoma.

Adult ; Aged ; Cell Nucleus ; enzymology ; Cytoplasm ; enzymology ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; Prostatic Hyperplasia ; enzymology ; pathology ; Protein Tyrosine Phosphatase, Non-Receptor Type 11 ; metabolism ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; metabolism ; Protein Tyrosine Phosphatases ; metabolism ; SH2 Domain-Containing Protein Tyrosine Phosphatases ; metabolism ; src-Family Kinases ; metabolism

Animals ; Colonic Neoplasms ; metabolism ; pathology ; Female ; Humans ; Liver Neoplasms ; metabolism ; secondary ; Lymphatic Metastasis ; Neoplasm Proteins ; metabolism ; Ovarian Neoplasms ; metabolism ; pathology ; Protein Tyrosine Phosphatases ; metabolism ; Stomach Neoplasms ; metabolism ; pathology

It has been demonstrated that signal transducer and activator of transcription-3 (STAT3) is activated after cerebral ischemia/reperfusion (I/R) in cortex and striatum. In this study, we investigated whether STAT3 was rapidly activated in hippocampus by cerebral ischemia without reperfusion in four-vessel occlusion (4-VO) model of Sprague-Dawley (SD) rats. The results showed that tyrosine phosphorylation and DNA binding activity of STAT3 was rapidly increased by ischemia. The p-STAT3 level in cytoplasm increased 5 min after occlusion and reached a peak at 10 min following ischemia (1.7 folds vs sham) by means of immunoblotting (IB). P-STAT3 in nucleus was gradually enhanced with its peak activity occurring at 30 min of ischemia (2.3 folds vs sham). Electrophoretic mobility shift assay (EMSA) with STAT3 probe demonstrated that DNA binding activity of STAT3 in nuclear extracts increased from 5 min and peaked at 30 min of ischemia (3.2 folds vs sham). These changes were prevented by genistein (a protein tyrosine kinase inhibitor) and antioxidant N-acetyl-L-cysteine (NAC), but promoted by sodium orthovanadate (a protein phosphatase inhibitor), which were administered to the SD rats 20 min before ischemia. These results indicate that the activation of STAT3 following cerebral ischemia may be modulated by PTK/PTP, and that this pathway may be of benefit to the adaptation of the hippocampal neurons to oxidative stress.
Animals ; Brain Ischemia ; metabolism ; physiopathology ; Hippocampus ; metabolism ; physiopathology ; Male ; Oxidative Stress ; physiology ; Phosphorylation ; Protein Tyrosine Phosphatases ; metabolism ; Protein-Tyrosine Kinases ; metabolism ; Rats ; Rats, Sprague-Dawley ; STAT3 Transcription Factor ; metabolism

OBJECTIVETo investigate the expression of phosphatase of regenerating liver-3 (PRL- 3) mRNA and evaluate its relationship with tumor invasion and metastasis in human colorectal carcinoma.

METHODSThe expression level of PRL-3 mRNA was examined semi-quantitatively in surgically resected tumor specimens, paired paratumor normal tissues from 46 CRC patients, metastatic lymph nodes and liver metastases from 18 cases with metastasis,adenoma tissues from 6 patients with colorectal adenoma (CRA). In addition,the mutation of PRL-3 gene was examined by PCR-SSCP.

RESULTSThe PRL-3 mRNA level was increased in primary CRC tissues as compared with paired paratumor normal tissues (1.6+/- 0.7 vs. 0.4+/- 0.1, P< 0.01), while no significant difference of its expression was found between CRA tissues and their adjacent normal mucosae (P> 0.05). However,the PRL-3 mRNA levels of liver metastases (2.1+/- 0.8) in 12 cases and metastatic lymph nodes (3.3+/- 1.0) in 6 cases were significantly higher compared with the matched primary lesions, normal tissues and negative-lymph nodes (P< 0.01). There was significant relation of the expression of PRL-3 mRNA with the clinicopathological features including Dukes stage, invasion depth and metastasis (P< 0.05), but no relation with sex,tumor size,degree of differentiation was found (P> 0.05). Abnormal electrolysis band was found in 1 of 6 cases with liver metastasis by PCR-SSCP analysis.

CONCLUSIONPRL-3 gene plays an important role in tumor invasion and metastasis and may associated with carcinogenesis and development of CRC. There might exist some unknown mechanisms of overexpression and mutation of PRL-3 gene in CRC.

Adult ; Aged ; Colorectal Neoplasms ; genetics ; pathology ; Female ; Gene Expression ; Humans ; Liver Neoplasms ; secondary ; Male ; Middle Aged ; Neoplasm Metastasis ; Neoplasm Proteins ; metabolism ; Protein Tyrosine Phosphatases ; metabolism ; RNA, Messenger ; metabolism

Reversible protein phosphorylation regulates multiple biochemical events. Mycobacterium tuberculosis phosphatases play important roles in regulating the pathogen physiology and interference of host signaling. They are also involved in the evasion of host immune response and blockage of the phagosome-lysosome fusion. Selective inhibition of phosphatase represents an ideal new avenue of anti-tuberculosis drug design. In this paper, we update the progresses about the regulation network of Mycobacterium tuberculosis phosphatases including MptpA, MptpB, MstP, SapM and their inhibitors. These serve as the basis for further antituberculosis drug target.
Acid Phosphatase ; antagonists & inhibitors ; metabolism ; Animals ; Antitubercular Agents ; pharmacology ; Bacterial Proteins ; antagonists & inhibitors ; metabolism ; Humans ; Mycobacterium tuberculosis ; drug effects ; enzymology ; Protein Tyrosine Phosphatases ; antagonists & inhibitors ; metabolism

OBJECTIVETo investigate the effects of protein tyrosine phosphatase-SHP2 and dual-specificity MAPK phosphatase-MKP5 on the activation of MAPKs and cell invasion induced by P2Y purinergic receptor in human prostate cancer cell lines with different metastatic potentials.

METHODSThe wide type (-wt) SHP2, mutant type (-cs) SHP2 and wide type (-wt) MKP5 cDNA expression vectors were constructed and stably transfected into 1E8 cells (highly metastatic) and/or 2B4 cells (non-metastatic). The tyrosine phosphorylation of SHP2 was examined by immunoprecipitation. The activation of ERK1/2 and p38 induced by P2Y receptor agonist ATP was analyzed by Western blot with phospho-specific antibodies against the dually phosphorylated, active forms of ERK1/2 and p38. The in-vitro invasive ability through Matrigel was measured by boyden-chamber assay.

RESULTSATP induced significant SHP2 phosphorylation, which was stronger and lasted longer in 1E8 than in 2B4. SHP2-wt enhanced the ERK1/2 activation induced by ATP in 2B4 cells, while SHP2-cs delayed and decreased this effect in 1E8 cells. Both SHP2-wt and SHP2-cs had no obvious influence on p38 activation. ATP stimulated cell invasion of both 1E8 and 2B4, while transfection of SHP2-wt into 2B4 cells further increased the invasive-stimulating ability of ATP (18.7% increase compared with ATP treatment alone). Transfection of SHP2-cs into 1E8 cells, however, antagonized the invasive-stimulating ability of ATP (40.9% decrease compared with ATP treated group). Up-regulation of MKP5-wt inhibited phosphorylation of p38 by ATP and reduced cell invasion stimulated by ATP (22.4% and 28.7% decrease compared with ATP treated group of 1E8 and 2B4, respectively).

CONCLUSIONSBoth SHP2 and MKP5 play some roles in P2Y receptor-mediated activation of MEK/ERK, p38 signaling pathways and prostate cancer invasion. SHP2 positively regulates ERK activation and prostate cancer invasion, whereas MKP5 inhibits the invasion by suppressing p38 activation.

Adenosine Triphosphate ; pharmacology ; Cell Line, Tumor ; DNA, Complementary ; genetics ; Dual-Specificity Phosphatases ; Genetic Vectors ; Humans ; Intracellular Signaling Peptides and Proteins ; genetics ; metabolism ; Male ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Mitogen-Activated Protein Kinase Phosphatases ; Neoplasm Invasiveness ; Phosphorylation ; Prostatic Neoplasms ; metabolism ; pathology ; Protein Tyrosine Phosphatase, Non-Receptor Type 11 ; Protein Tyrosine Phosphatases ; genetics ; metabolism ; Receptors, Purinergic P2 ; physiology ; Signal Transduction ; Transfection ; p38 Mitogen-Activated Protein Kinases ; metabolism

Branchio-oto syndrome (BOS)/branchio-oto-renal syndrome (BORS) is a kind of autosomal dominant heterogeneous disorder. These diseases are mainly characterized by hearing impairment and abnormal phenotype of ears, accompanied by renal malformation and branchial cleft anomalies including cyst or fistula, with an incidence of 1/40 000 in human population. Otic anormalies are one of the most obvious clinical manifestations of BOS/BORS, including deformities of external, middle, inner ears and hearing loss with conductive, sensorineural or mix, ranging from mild to profound loss. Temporal bone imaging could assist in the diagnosis of middle ear and inner ear malformations for clinicians. Multiple methods including direct sequencing combined with next generation sequencing (NGS), multiplex ligation-dependent probe amplification (MLPA), or array-based comparative genomic hybridization (aCGH) can effectively screen and identify pathogenic genes and/or variation types of BOS/BORS. About 40% of patients with BOS/BORS carry aberrations of EYA1 gene which is the most important cause of BOS/BORS. A total of 240 kinds of pathogenic variations of EYA1 have been reported in different populations so far, including frameshift, nonsense, missense, aberrant splicing, deletion and complex rearrangements. Human Endogenous Retroviral sequences (HERVs) may play an important role in mediating EYA1 chromosomal fragment deletion mutations caused by non-allelic homologous recombination. EYA1 encodes a phosphatase-transactivator cooperated with transcription factors of SIX1, participates in cranial sensory neurogenesis and development of branchial arch-derived organs, then regulates the morphological and functional differentiation of the outer ear, middle ear and inner ear toward normal tissues. In addition, pathogenic mutations of SIX1 and SIX5 genes can also cause BOS/BORS. Variations of these genes mentioned above may cause disease by destroying the bindings between SIX1-EYA1, SIX5-EYA1 or SIX1-DNA. However, the role of SIX5 gene in the pathogenesis of BORS needs further verification.
Branchio-Oto-Renal Syndrome/pathology* ; Chromosome Deletion ; Comparative Genomic Hybridization ; Genetic Research ; Homeodomain Proteins/genetics* ; Humans ; Intracellular Signaling Peptides and Proteins ; Nuclear Proteins/metabolism* ; Pedigree ; Protein Tyrosine Phosphatases/metabolism*

Diabetes mellitus is caused by deficiency of insulin secretion from the pancreatic islet beta cells and/or insulin resistance in liver, muscle and adipocytes, resulting in glucose intolerance and hyperglycemia. Several protein tyrosine phosphatases, such as PTP1B (PTPN1), TCPTP (PTPN2), LYP (PTPN22), PTPIA-2, PTPMEG2 (PTPN9) or OSTPTP are involved in insulin signaling pathway, insulin secretion and autoreactive attack to pancreatic beta cells. Genetic mutation or overexpression of these phosphotases has been found to cause or increase the risk of diabetes mellitus. Some population with high risk for type 2 diabetes has overexpressed PTP1B, a prototypical tyrosine phosphatase which down-regulates insulin and leptin signal transduction. Animal PTP1B knockout model and PTP1B specific inhibitor cellular studies indicate PTP1B may serve as a therapeutic target for type 2 diabetes. TCPTP shares more than 70% sequence identity with PTP1B in their catalytic domain. TCPTP dephosphorylates tyrosine phosphorylated substrates overlapping with PTP1B but also has its own distinct dephosphorylation sites and functions. Recent research indicates TCPTP may have role in type 1 diabetes via dysregultaion of cytokine-mediated immune responses or pancreatic beta cell apoptosis. The tyrosine phosphatase LYP, which down-regulates LCK activity in T cell response, can become mutated as R620W which is highly correlated to type 1 diabetes. LYP R620W may be a gain of function mutation which suppresses TCR signaling. Patients bearing the R620W mutant have impaired T cell responses and increased populations of (CD45RO+CD45RA-) CD4+ T cells. A detailed elucidation of mechanism of R620W in type 1 diabetes and specific LYP inhibitor development will help characterize LYP R620W as a therapeutic target. A receptor tyrosine phosphatase, PTPIA-2/beta is a major autoantigen of type 1 diabetes. A diagnosis kit identifying PTPIA-2/beta autoantibodies is valuable in early detection and prevention of type 1 diabetes. In addition, other phosphatase like OSTPTP and PTPMEG2 are involved in type 2 diabetes via regulation of insulin production, beta cell growth or insulin signaling. Research into understanding the mechanism of these tyrosine phosphatases in diabetes, such as their precise functions in the regulation of insulin secretion, the insulin response and the immune response will strengthen our knowledge of diabetes pathophysiology which may result in new diagnostic and therapeutic strategies for diabetes.
Animals ; Diabetes Mellitus ; enzymology ; Diabetes Mellitus, Type 1 ; enzymology ; Diabetes Mellitus, Type 2 ; enzymology ; Humans ; Protein Tyrosine Phosphatase, Non-Receptor Type 1 ; genetics ; metabolism ; Protein Tyrosine Phosphatase, Non-Receptor Type 2 ; genetics ; metabolism ; Protein Tyrosine Phosphatase, Non-Receptor Type 22 ; genetics ; metabolism ; Protein Tyrosine Phosphatases, Non-Receptor ; classification ; genetics ; metabolism

OBJECTIVETo investigate the role of cytoplasmic domain of integrin alpha IIb in platelet signal transduction.

METHODSBinding capacity of integrin alpha IIb(R995A) to antibody platelet activation complex-1 (PAC-1) and pp125 focal adhesion kinase (FAK) phosphorylation of cells were detected by flow cytometry, immune precipitation, and Western blotting.

RESULTSWithout activation, wild-type alpha IIb beta3 Chinese hamster ovary (CHO) cells failed to bind to PAC-1, but mutant chimera alpha IIb(R995A)beta3 CHO cells were able to bind with PAC-1. Furthermore, phosphorylation of pp125 (FAK) in wild-type alpha IIb beta3 CHO cells occured only when cells were adhered to fibrinogen, but could not be detected in bovine serum albumin suspension. However in the mutant chimera group, it could be detected in both conditions.

CONCLUSIONThe mutation in integrin alpha IIb(R995A) alters its affinity state as a receptor, thus also mediating cytoplasmic signal transduction leading to the phosphorylation of pp125 (FAK) without ligand binding.

Animals ; Blood Platelets ; metabolism ; CHO Cells ; Cell Adhesion ; Cricetinae ; Cricetulus ; Cytoplasm ; metabolism ; Dual Specificity Phosphatase 2 ; Focal Adhesion Kinase 1 ; Focal Adhesion Protein-Tyrosine Kinases ; Humans ; Phosphorylation ; Platelet Glycoprotein GPIIb-IIIa Complex ; genetics ; metabolism ; physiology ; Point Mutation ; Protein Phosphatase 2 ; Protein Tyrosine Phosphatases ; metabolism ; Protein-Tyrosine Kinases ; metabolism ; Signal Transduction ; Transfection