Sustained activation of extracellular signal-regulated kinase (ERK) drives pathologies caused by mutations in fibroblast growth factor receptors (FGFRs). We previously identified the inositol phosphatase SHIP2 (also known as INPPL1) as an FGFR-interacting protein and a target of the tyrosine kinase activities of FGFR1, FGFR3, and FGFR4. We report that loss of SHIP2 converted FGF-mediated sustained ERK activation into a transient signal and rescued cell phenotypes triggered by pathologic FGFR-ERK signaling. Mutant forms of SHIP2 lacking phosphoinositide phosphatase activity still associated with FGFRs and did not prevent FGF-induced sustained ERK activation, demonstrating that the adaptor rather than the catalytic activity of SHIP2 was required. SHIP2 recruited Src family kinases to the FGFRs, which promoted FGFR-mediated phosphorylation and assembly of protein complexes that relayed signaling to ERK. SHIP2 interacted with FGFRs, was phosphorylated by active FGFRs, and promoted FGFR-ERK signaling at the level of phosphorylation of the adaptor FRS2 and recruitment of the tyrosine phosphatase PTPN11. Thus, SHIP2 is an essential component of canonical FGF-FGFR signal transduction and a potential therapeutic target in FGFR-related disorders.

• MeSH
• adaptorové proteiny signální transdukční genetika   metabolismus   MeSH
• aktivace enzymů MeSH
• extracelulárním signálem regulované MAP kinasy genetika   metabolismus   MeSH
• fosfatidylinositol-3,4,5-trisfosfát-5-fosfatasy genetika   metabolismus   MeSH
• fosforylace MeSH
• HEK293 buňky MeSH
• lidé MeSH
• MAP kinasový signální systém * MeSH
• membránové proteiny genetika   metabolismus   MeSH
• nádorové buněčné linie MeSH
• receptory fibroblastových růstových faktorů genetika   metabolismus   MeSH
• skupina kinas odvozených od src-genu genetika   metabolismus   MeSH
• tyrosinfosfatasa nereceptorového typu 11 genetika   metabolismus   MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Liver fibrosis is characterized by the activation and migration of hepatic stellate cells (HSCs), followed by matrix deposition. Recently, several studies have shown the importance of extracellular vesicles (EVs) derived from liver cells, such as hepatocytes and endothelial cells, in liver pathobiology. While most of the studies describe how liver cells modulate HSC behavior, an important gap exists in the understanding of HSC-derived signals and more specifically HSC-derived EVs in liver fibrosis. Here, we investigated the molecules released through HSC-derived EVs, the mechanism of their release, and the role of these EVs in fibrosis. Mass spectrometric analysis showed that platelet-derived growth factor (PDGF) receptor-alpha (PDGFRα) was enriched in EVs derived from PDGF-BB-treated HSCs. Moreover, patients with liver fibrosis had increased PDGFRα levels in serum EVs compared to healthy individuals. Mechanistically, in vitro tyrosine720-to-phenylalanine mutation on the PDGFRα sequence abolished enrichment of PDGFRα in EVs and redirected the receptor toward degradation. Congruently, the inhibition of Src homology 2 domain tyrosine phosphatase 2, the regulatory binding partner of phosphorylated tyrosine720, also inhibited PDGFRα enrichment in EVs. EVs derived from PDGFRα-overexpressing cells promoted in vitro HSC migration and in vivo liver fibrosis. Finally, administration of Src homology 2 domain tyrosine phosphatase 2inhibitor, SHP099, to carbon tetrachloride-administered mice inhibited PDGFRα enrichment in serum EVs and reduced liver fibrosis. CONCLUSION: PDGFRα is enriched in EVs derived from PDGF-BB-treated HSCs in an Src homology 2 domain tyrosine phosphatase 2-dependent manner and these PDGFRα-enriched EVs participate in development of liver fibrosis. (Hepatology 2018;68:333-348).

• MeSH
• dospělí MeSH
• extracelulární vezikuly metabolismus   MeSH
• jaterní cirhóza etiologie   metabolismus   MeSH
• jaterní hvězdicovité buňky metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• myši inbrední C57BL MeSH
• pohyb buněk MeSH
• růstový faktor odvozený z trombocytů - receptor alfa metabolismus   MeSH
• tyrosinfosfatasa nereceptorového typu 11 metabolismus   MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Juvenile myelomonocytic leukemia (JMML) is an aggressive myeloproliferative disorder of early childhood characterized by mutations activating RAS signaling. Established clinical and genetic markers fail to fully recapitulate the clinical and biological heterogeneity of this disease. Here we report DNA methylome analysis and mutation profiling of 167 JMML samples. We identify three JMML subgroups with unique molecular and clinical characteristics. The high methylation group (HM) is characterized by somatic PTPN11 mutations and poor clinical outcome. The low methylation group is enriched for somatic NRAS and CBL mutations, as well as for Noonan patients, and has a good prognosis. The intermediate methylation group (IM) shows enrichment for monosomy 7 and somatic KRAS mutations. Hypermethylation is associated with repressed chromatin, genes regulated by RAS signaling, frequent co-occurrence of RAS pathway mutations and upregulation of DNMT1 and DNMT3B, suggesting a link between activation of the DNA methylation machinery and mutational patterns in JMML.

• MeSH
• antitumorózní látky terapeutické užití   MeSH
• biopsie MeSH
• chromatin genetika   metabolismus   MeSH
• dítě MeSH
• DNA-(cytosin-5-)methyltransferasa metabolismus   MeSH
• DNA-(cytosin-5)-methyltransferasa 1 metabolismus   MeSH
• epigenomika MeSH
• juvenilní myelomonocytární leukemie genetika   mortalita   patologie   terapie   MeSH
• kojenec MeSH
• lidé MeSH
• metylace DNA * MeSH
• mutace MeSH
• mutační analýza DNA MeSH
• Noonanové syndrom genetika   patologie   MeSH
• předškolní dítě MeSH
• prognóza MeSH
• prospektivní studie MeSH
• protoonkogenní proteiny c-cbl MeSH
• protoonkogenní proteiny p21(ras) genetika   metabolismus   MeSH
• regulace genové exprese u leukemie MeSH
• signální transdukce genetika   MeSH
• transplantace hematopoetických kmenových buněk MeSH
• tyrosinfosfatasa nereceptorového typu 11 genetika   metabolismus   MeSH
• upregulace MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• multicentrická studie MeSH
• pozorovací studie MeSH
• práce podpořená grantem MeSH

Aberrant DNA methylation at specific genetic loci is a key molecular feature of juvenile myelomonocytic leukemia (JMML) with poor prognosis. Using quantitative high-resolution mass spectrometry, we identified RASA4 isoform 2, which maps to chromosome 7 and encodes a member of the GAP1 family of GTPase-activating proteins for small G proteins, as a recurrent target of isoform-specific DNA hypermethylation in JMML (51% of 125 patients analyzed). RASA4 isoform 2 promoter methylation correlated with clinical parameters predicting poor prognosis (older age, elevated fetal hemoglobin), with higher risk of relapse after hematopoietic stem cell transplantation, and with PTPN11 mutation. The level of isoform 2 methylation increased in relapsed cases after transplantation. Interestingly, most JMML cases with monosomy 7 exhibited hypermethylation on the remaining RASA4 allele. The results corroborate the significance of epigenetic modifications in the phenotype of aggressive JMML.

• MeSH
• chemorezistence * MeSH
• CpG ostrůvky MeSH
• dítě MeSH
• juvenilní myelomonocytární leukemie diagnóza   metabolismus   patologie   MeSH
• kojenec MeSH
• lidé MeSH
• lidské chromozomy, pár 7 MeSH
• metylace DNA * MeSH
• mladiství MeSH
• monozomie MeSH
• mutace MeSH
• předškolní dítě MeSH
• prognóza MeSH
• promotorové oblasti (genetika) MeSH
• protein - isoformy genetika   metabolismus   MeSH
• proteiny aktivující GTPasu ras genetika   metabolismus   MeSH
• tyrosinfosfatasa nereceptorového typu 11 genetika   metabolismus   MeSH
• umlčování genů MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Transmembrane adaptor proteins are membrane-anchored proteins consisting of a short extracellular part, a transmembrane domain, and a cytoplasmic part with various protein-protein interaction motifs but lacking any enzymatic activity. They participate in the regulation of various signaling pathways by recruiting other proteins to the proximity of cellular membranes where the signaling is often initiated and propagated. In this work, we show that LST1/A, an incompletely characterized protein encoded by MHCIII locus, is a palmitoylated transmembrane adaptor protein. It is expressed specifically in leukocytes of the myeloid lineage, where it localizes to the tetraspanin-enriched microdomains. In addition, it binds SHP-1 and SHP-2 phosphatases in a phosphotyrosine-dependent manner, facilitating their recruitment to the plasma membrane. These data suggest a role for LST1/A in negative regulation of signal propagation.

• MeSH
• buněčná membrána metabolismus   MeSH
• HEK293 buňky MeSH
• HeLa buňky MeSH
• hlavní histokompatibilní komplex fyziologie   MeSH
• Jurkat buňky MeSH
• lidé MeSH
• membránové proteiny chemie   genetika   metabolismus   MeSH
• molekulární sekvence - údaje MeSH
• myeloidní buňky cytologie   metabolismus   MeSH
• plakiny metabolismus   MeSH
• primární buněčná kultura MeSH
• pseudopodia metabolismus   MeSH
• sekvence aminokyselin MeSH
• signální transdukce fyziologie   MeSH
• terciární struktura proteinů fyziologie   MeSH
• transport proteinů fyziologie   MeSH
• tyrosinfosfatasa nereceptorového typu 11 metabolismus   MeSH
• tyrosinfosfatasa nereceptorového typu 6 metabolismus   MeSH
• U937 buňky MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH