Male ; Meiosis ; Protein Tyrosine Phosphatase, Non-Receptor Type 11 ; Spermatocytes ; Spermatogenesis ; Spermatogonia ; Tyrosine

The Src homology-2 domain-containing phosphatase SHP-2 encoded by PTPN11 is an essential component in several signaling pathways.Different types of mutation in SHP-2 have been confirmed in several types of leukemia and solid tumors. Elucidation of the events underlying Shp2-evoked transformation may provide new insights into the novel targets for anti-cancer therapy.
Humans ; Protein Tyrosine Phosphatase, Non-Receptor Type 11 ; chemistry ; metabolism ; physiology

Objective: To analyze the clinical phenotype and screen the genetic mutations of hereditary deafness in three deaf families to clarify their molecular biology etiology. Methods: From January 2019 to January 2020, three deaf children and family members were collected for medical history, physical examination, audiology evaluation, electrocardiogram and cardiac color Doppler ultrasound, temporal bone CT examination, and peripheral blood DNA was obtained for high-throughput sequencing of deafness genes. Sanger sequencing was performed to verify the variant sites among family members. The pathogenicity of the variants was evaluated according to the American College of Medical Genetics and Genomics. Results: The probands in the three families had deafness phenotypes. In family 1, proband had multiple lentigines, special facial features, growth retardation, pectus carinatum, abnormal skin elasticity, cryptorchidism and other manifestations. In family 2, proband had special facial features, growth retardation and abnormal heart, and the proband in family 3 had growth retardation and abnormal electrocardiogram. Genetic testing of three families detected three heterozygous mutations in the PTPN11 gene: c.1391G>C (p.Gly464Ala), c.1510A>G (p.Met504Val), c.1502G>A (p.Arg501Lys). All three sites were missense mutations, and the mutation sites were highly conserved among multiple homologous species. Based on clinical manifestations and genetic test results, proband 1 was diagnosed with multiple lentigines Noonan syndrome, and probands 2 and 3 were diagnosed with Noonan syndrome. Conclusion: Missense mutations in the PTPN11 gene may be the cause of the disease in the three deaf families. This study enriches the clinical phenotype and mutation spectrum of the PTPN11 gene in the Chinese population.
Deafness/genetics* ; Genetic Testing ; Hearing Loss/genetics* ; Humans ; Male ; Mutation ; Phenotype ; Protein Tyrosine Phosphatase, Non-Receptor Type 11/genetics*

Mutation of leucine-rich repeat kinase 2 (LRRK2) causes an autosomal dominant and late-onset familial Parkinson's disease (PD). Recently, we reported that LRRK2 directly binds to and phosphorylates the threonine 474 (T474)-containing Thr-X-Arg(Lys) (TXR) motif of focal adhesion kinase (FAK), thereby inhibiting the phosphorylation of FAK at tyrosine (Y) 397 residue (pY397-FAK), which is a marker of its activation. Mechanistically, however, it remained unclear how T474-FAK phosphorylation suppressed FAK activation. Here, we report that T474-FAK phosphorylation could inhibit FAK activation via at least two different mechanisms. First, T474 phosphorylation appears to induce a conformational change of FAK, enabling its N-terminal FERM domain to autoinhibit Y397 phosphorylation. This is supported by the observation that the levels of pY397-FAK were increased by deletion of the FERM domain and/or mutation of the FERM domain to prevent its interaction with the kinase domain of FAK. Second, pT474-FAK appears to recruit SHP-2, which is a phosphatase responsible for dephosphorylating pY397-FAK. We found that mutation of T474 into glutamate (T474E-FAK) to mimic phosphorylation induced more strong interaction with SHP-2 than WT-FAK, and that pharmacological inhibition of SHP-2 with NSC-87877 rescued the level of pY397 in HEK293T cells. These results collectively show that LRRK2 suppresses FAK activation through diverse mechanisms that include the promotion of autoinhibition and/or the recruitment of phosphatases, such as SHP-2.
Focal Adhesion Protein-Tyrosine Kinases ; Glutamic Acid ; Parkinson Disease ; Phosphoric Monoester Hydrolases ; Phosphorylation ; Phosphotransferases ; Protein Tyrosine Phosphatase, Non-Receptor Type 11* ; Threonine ; Tyrosine*

BACKGROUND: The precise mechanism by which CTLA-4 regulates T cell immune responses is still not fully understood. Previously we proposed that CTLA-4 could downregulate T cell function by modulating a signaling cascade initiated from the T cell receptor complex. The evidence for this notion comes from our findings that CTLA-4 associated with the T cell receptor zeta (TCR zeta) chain, and hence regulated TCR zeta phosphorylation by co-associated SHP-2 tyrosine phosphatase (1). In this report, we investigated whether any other signaling molecules could be involved in the CTLA-4 signaling pathway. METHODS: We have taken biochemical approaches, such as immunoprecipitation followed by autoradiography or immunoblotting, to identify the molecules associated with CTLA-4. To perform these assays, we used activated primary T cells and ectopically transfected 293 cells. Various truncation mutants of CTLA-4 were used to map the interaction site on CTLA-4. RESULTS: We found that in addition to TCR zeta and SHP-2, a recently cloned small adaptor molecule, SAP (SLAM-associated protein), was also able to associate with CTLA-4. We identified the domain of SAP association in CTLA-4 being a motif involving GVYVKM. This motif has been previously found to bind SHP-2 through its phosphorylated tyrosine interaction with SH-2 domain of SHP-2. Indeed, co-expression of SAP and SHP-2 reduced their binding to CTLA-4 significantly, suggesting that SAP and SHP-2 compete for the common binding site, GVYVKM. Thus, by blocking SHP-2 recruitment SAP could function as a negative regulator of CTLA-4. CONCLUSION: Taken together, our data suggest the existence of complicate signaling cascade in regulating CTLA-4 function, and further provide evidence that SAP can act either as a positive or negative regulator depending on the nature of the associating receptors.
Autoradiography ; Binding Sites ; Clone Cells ; Immunoblotting ; Immunoprecipitation ; Phosphorylation ; Protein Tyrosine Phosphatase, Non-Receptor Type 11 ; Protein-Tyrosine Kinases ; Receptors, Antigen, T-Cell ; T-Lymphocytes ; Transfection ; Tyrosine

In order to express and purify the catalytic domain of SHP-1/SHP-2 (named as D1C and D2C respectively) and determine their kinetics, the constructed D1C and D2C plasmids were transformed into Escherichia coli BL21 and the expression was induced with IPTG. The harvested cells were suspended in extraction buffer. After sonication, the solution was applied to HPLC and the results were confirmed by SDS-PAGE. The purified peptides were further subjected to kinetic specificity study using synthetic phosphotyrosine (pY) as substrate by malachite green method and analyzed by Lineweaver-Burk plot calculation. From this study, we found D1C and D2C were expressed successfully in soluble state in Escherichia coli BL21 and purified efficiently with HPLC system. The molecular weight of D1C was 34.6 kD, and its Michaelis constant (K(m)) was 2.04 mmol catalytic constant (K(cat)) was 44.98 s(-1), specific constant (K(cat)/K(m)) was 22.05 L/(mmol x s); the molecular weigh of D2C was 35.3 kD, and its Michaelis constant (K(m)) was 2.47 mmol, catalytic constant (K(cat)) was 27.45 s(-1), specific constant (K(cat)/K(m)) was L/(mmol x s). The enzyme activity of D1C is stronger than that of D2C.
Catalytic Domain ; Chromatography, High Pressure Liquid ; Escherichia coli ; genetics ; metabolism ; Kinetics ; Plasmids ; Protein Tyrosine Phosphatase, Non-Receptor Type 11 ; genetics ; metabolism ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; genetics ; metabolism ; Recombinant Proteins ; genetics ; metabolism

OBJECTIVETo detect the expression of PTPN11 gene in acute myeloid leukemia (AML) cell line and to explore the effects of PTPN11 over expressing on proliferation and apotosis of AML cell lines.

METHODSThe expression of PTPN11 in AML cell lines（HEL,U937, K562, KG-1, HL -60） was detected by RT-PCR, Q-PCR and Western blot. The PTPN11 gene was amplified by RT-PCR. PTPN11 DNA fragement and the lentiviral vector PCDH-CD513B were digested by BamHI and EcoRI, and then ligated by T4 DNA ligase. Recombinant lentivirus was generated by co-transfection of three-plasmids into 293FT cells using lipofectamine 2000. Then Q-PCR and Western blot were used to detect the expression of PTPN11 in the lentivirus infected HEL and U937 cells. The CCK-8 and Annexin V/7-AAD assays were performed to evaluate effects of PTPN11 on proliferation, apoptosis of HEL and U937 cells.

RESULTSAll 5 AML cell lines expressed the PTPN11 gene, restriction analysis and gene sequencing confirmed that recombinant lentiviral vector was successfully constructed. After transfection of cells with the lentivirus, the recombinant plasmid could stably up-regulate the expression of PTPN11. Analysis of the proliferation and apoptosis of transfected AML cells indicated that as compared with the control group, the OD values of over-expression group were significantly higher and the apoptotic rates were significantly lower (P<0.05).

CONCLUSIONPTPN11 is expressed in all the 5 AML cell lines. The lentiviral expression vector carrying human PTPN11 and the engineered HEL and U937 cell lines stably up-regulating PTPN11 gene expression are successfully obtained. Over-expression of PTPN11 promotes the proliferation of AML cell lines and inhibit then apoptosis.

Apoptosis ; Cell Line, Tumor ; Gene Expression ; Genetic Vectors ; Humans ; Lentivirus ; Leukemia, Myeloid, Acute ; Plasmids ; Protein Tyrosine Phosphatase, Non-Receptor Type 11 ; Transfection

OBJECTIVETo study gene mutations and clinical features in children with juvenile myelomonocytic leukemia (JMML).

METHODSThe clinical data of 14 children who were diagnosed with JMML and were examined for the detection of common gene mutations were retrospectively analyzed.

RESULTSEleven (79%) out of 14 cases were male, and 3 (21%) were female. The median age at diagnosis was 2.0 years (age range: 0.6-6.0 years). Among 14 cases, there were 4 cases (29%) with PTPN11 mutation, 3 cases (21%) with N-RAS mutation, 1 case (7%) with PTPN11 mutation and K-RAS mutation, and 6 cases (43%) without any mutation. All four cases in the PTPN11 mutation group were male, and their median age was 2.5 years; interval from onset to diagnosis was 1.0 month; the white blood cell (WBC) count and absolute monocytes in peripheral blood were significantly higher, while the platelet (PLT) count was lower, as compared with the other three groups; they were followed up, and 3 cases died and 1 case had a progressive disease. In the N-RAS mutation group, there were two male cases and one female case, and their median age was 2.0 years; interval from onset to diagnosis was 13.7 months; after follow-up, 2 cases died and 1 case did not have an obviously progressive disease.

CONCLUSIONSPTPN11 mutation is the most common mutation in JMML. The cases with PTPN11 mutation often have higher WBC count and absolute monocytes in peripheral blood, a lower PLT count, and a rapid disease progression, and their clinical outcomes are poor. The cases with N-RAS mutation have a slow disease progression. The clinical characteristics of the patients with compound mutations are not sure because of the small number of cases, and further clinical observation is indispensable.

Child ; Child, Preschool ; Female ; Genes, ras ; Humans ; Infant ; Leukemia, Myelomonocytic, Juvenile ; blood ; genetics ; Male ; Mutation ; Protein Tyrosine Phosphatase, Non-Receptor Type 11 ; genetics ; Retrospective Studies

OBJECTIVETo investigate the effects of Bortezomib on proliferation, apoptosis and SHP-2 gene expression of lymphoma Jurkat cells and Raji cells.

METHODSMethylthiazoly tetrazolium assay (MTT) was used to observe the proliferation of Jurkat cells and Raji cells treated with bortezomib in different doses. Cell apoptosis was detected by morphological examination and flow cytometry. The level of SHP-2 mRNA expression before and after the treatment with bortezomib was measured by RT-PCR.

RESULTSBortezomib could inhibit the proliferation of Jurkat and Raji cells and induce their apoptosis with time-and dose-dependent manner. After treatment with 5-100 nmol/L bortezomib, the expression of SHP-2 in Jurkat cells and Raji cells was upregulated.

CONCLUSIONBortezomib can inhibit the proliferation and induc the apoptosis of Jurkat and Raji cells obviously, upregulate the expression of SHP-2 mRNA, suggesting that the SHP-2 may participate in regulation of bortezomib induced apoptosis of Jurkat cells and Raji cells.

Apoptosis ; Bortezomib ; Cell Line, Tumor ; Cell Proliferation ; Flow Cytometry ; Gene Expression Regulation, Leukemic ; Humans ; Lymphoma ; genetics ; pathology ; Protein Tyrosine Phosphatase, Non-Receptor Type 11

This study was aimed to explore the frequency of PTPN11 mutation in children with leukemia and its clinical significance. Genomic DNAs were extracted from peripheral leukocytes of 131 patients with leukemia, including 101 cases of ALL, 26 cases of AML, 3 cases of CML and 1 case of juvenil myelomonocytic leukemia (JMML). The sequences of PTPN11 exons 3, 8, 13 were amplified by polymerase chain reaction (PCR), and the clinical characteristics of positive patients were analyzed. The results indicated that the PTPN11 mutation was found in 10 cases (9.9%) from newly diagnosed 101 cases of ALL. Grouping the newly diagnosed ALL children by various clinical features, it was found that the PTPN11 mutation did not show associations with sex, age, white blood cell (WBC) count, prednisone test sensitivity, clinical risk and disease recurrences at the first visit (P > 0.05). PTPN11 mutations were found in 2 cases out of 26 AML patients, including one AML-M(2) and one AML-M(4). No PTPN11 mutation in 3 CML patients was found. Exon 13 mutation of PTPN11 gene was found in 1 case of JMML. It is concluded that the E76 of exon 3 is the hot spot of PTPN11 mutation in children leukemia. The novel G503E (1508G > A) mutation is detected in one JMML patient. The PTPN11 mutation does not associate with the sex, age, WBC count, prednisone sensitive test and early recurrence.
Adolescent ; Base Sequence ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Leukemia ; genetics ; Male ; Mutation ; Protein Tyrosine Phosphatase, Non-Receptor Type 11 ; genetics