Fibroblast growth factors (FGFs) deliver extracellular signals that govern many developmental and regenerative processes, but the mechanisms regulating FGF signaling remain incompletely understood. Here, we explored the relationship between intrinsic stability of FGF proteins and their biological activity for all 18 members of the FGF family. We report that FGF1, FGF3, FGF4, FGF6, FGF8, FGF9, FGF10, FGF16, FGF17, FGF18, FGF20, and FGF22 exist as unstable proteins, which are rapidly degraded in cell cultivation media. Biological activity of FGF1, FGF3, FGF4, FGF6, FGF8, FGF10, FGF16, FGF17, and FGF20 is limited by their instability, manifesting as failure to activate FGF receptor signal transduction over long periods of time, and influence specific cell behavior in vitro and in vivo. Stabilization via exogenous heparin binding, introduction of stabilizing mutations or lowering the cell cultivation temperature rescues signaling of unstable FGFs. Thus, the intrinsic ligand instability is an important elementary level of regulation in the FGF signaling system.

• MeSH
• chondrosarkom genetika   metabolismus   patologie   MeSH
• cirkulární dichroismus MeSH
• fibroblastové růstové faktory chemie   klasifikace   genetika   metabolismus   MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• mutace genetika   MeSH
• mutantní proteiny chemie   metabolismus   MeSH
• nádorové buňky kultivované MeSH
• nádory kostí genetika   metabolismus   patologie   MeSH
• nádory prsu genetika   metabolismus   patologie   MeSH
• proliferace buněk * MeSH
• signální transdukce * MeSH
• stabilita proteinů MeSH
• teplota MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fibroblastové růstové faktory MeSH
• mutantní proteiny MeSH

In 1994, the field of bone biology was significantly advanced by the discovery that activating mutations in the fibroblast growth factor receptor 3 (FGFR3) receptor tyrosine kinase (TK) account for the common genetic form of dwarfism in humans, achondroplasia (ACH). Other conditions soon followed, with the list of human disorders caused by FGFR3 mutations now reaching at least 10. An array of vastly different diagnoses is caused by similar mutations in FGFR3, including syndromes affecting skeletal development (hypochondroplasia [HCH], ACH, thanatophoric dysplasia [TD]), skin (epidermal nevi, seborrhaeic keratosis, acanthosis nigricans), and cancer (multiple myeloma [MM], prostate and bladder carcinoma, seminoma). Despite many years of research, several aspects of FGFR3 function in disease remain obscure or controversial. As FGFR3-related skeletal dysplasias are caused by growth attenuation of the cartilage, chondrocytes appear to be unique in their response to FGFR3 activation. However, the reasons why FGFR3 inhibits chondrocyte growth while causing excessive cellular proliferation in cancer are not clear. Likewise, the full spectrum of molecular events by which FGFR3 mediates its signaling is just beginning to emerge. This article describes the challenging journey to unravel the mechanisms of FGFR3 function in skeletal dysplasias, the extraordinary cellular manifestations of FGFR3 signaling in chondrocytes, and finally, the progress toward therapy for ACH and cancer.

• MeSH
• chondrocyty metabolismus   patologie   MeSH
• chrupavka abnormality   metabolismus   MeSH
• fibroblastové růstové faktory genetika   metabolismus   MeSH
• fosfatidylinositol-3-kinasy genetika   metabolismus   MeSH
• kosti a kostní tkáň abnormality   metabolismus   MeSH
• kůže metabolismus   patologie   MeSH
• letální geny MeSH
• lidé MeSH
• MAP kinasový signální systém genetika   MeSH
• mezibuněčná komunikace MeSH
• mutace MeSH
• nádory kůže genetika   metabolismus   patologie   MeSH
• natriuretický peptid typu C genetika   metabolismus   MeSH
• osteochondrodysplazie genetika   metabolismus   patologie   MeSH
• proliferace buněk MeSH
• receptor fibroblastových růstových faktorů, typ 3 * genetika   metabolismus   MeSH
• regulace genové exprese MeSH
• signální transdukce MeSH
• transkripční faktor STAT1 genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• FGFR3 protein, human MeSH Prohlížeč
• fibroblastové růstové faktory MeSH
• fosfatidylinositol-3-kinasy MeSH
• natriuretický peptid typu C MeSH
• receptor fibroblastových růstových faktorů, typ 3 * MeSH
• STAT1 protein, human MeSH Prohlížeč
• transkripční faktor STAT1 MeSH

LDL-related protein 6 (LRP6) is a coreceptor of WNTs and a key regulator of the WNT/β-catenin pathway. Upon activation, LRP6 is phosphorylated within its intracellular PPPS/TP motifs. These phosphorylated motifs are required to recruit axin and to inhibit glycogen synthase kinase 3 (GSK3), two basic components of the β-catenin destruction complex. On the basis of a kinome-wide small interfering RNA (siRNA) screen and confirmative biochemical analysis, we show that several proline-directed mitogen-activated protein kinases (MAPKs), such as p38, ERK1/2, and JNK1 are sufficient and required for the phosphorylation of PPPS/TP motifs of LRP6. External stimuli, which control the activity of MAPKs, such as phorbol esters and fibroblast growth factor 2 (FGF2) control the choice of the LRP6-PPPS/TP kinase and regulate the amplitude of LRP6 phosphorylation and WNT/β-catenin-dependent transcription. Our findings suggest that cells not only recruit one dedicated LRP6 kinase but rather select their LRP6 kinase depending on cell type and the external stimulus. Moreover, direct phosphorylation of LRP6 by MAPKs provides a unique point for convergence between WNT/β-catenin signaling and mitogenic pathways.

• MeSH
• aminokyselinové motivy MeSH
• beta-katenin metabolismus   MeSH
• buněčné linie MeSH
• fosforylace MeSH
• krysa rodu Rattus MeSH
• LDL receptor related protein 6 MeSH
• LDL-receptory metabolismus   MeSH
• lidé MeSH
• malá interferující RNA genetika   MeSH
• MAP kinasový signální systém MeSH
• mitogenem aktivovaná proteinkinasa 8 metabolismus   MeSH
• mitogenem aktivované proteinkinasy p38 metabolismus   MeSH
• mitogenem aktivované proteinkinasy antagonisté a inhibitory   genetika   metabolismus   MeSH
• nádorové buňky kultivované MeSH
• proteiny související s LDL-receptory chemie   genetika   metabolismus   MeSH
• proteiny Wnt metabolismus   MeSH
• signální transdukce MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, N.I.H., Intramural MeSH
• Názvy látek
• beta-katenin MeSH
• CTNNB1 protein, human MeSH Prohlížeč
• LDL receptor related protein 6 MeSH
• LDL-receptory MeSH
• LRP6 protein, human MeSH Prohlížeč
• malá interferující RNA MeSH
• mitogenem aktivovaná proteinkinasa 8 MeSH
• mitogenem aktivované proteinkinasy p38 MeSH
• mitogenem aktivované proteinkinasy MeSH
• proteiny související s LDL-receptory MeSH
• proteiny Wnt MeSH

Oncogenic activation of the RAS-ERK MAP kinase signaling pathway can lead to uncontrolled proliferation but can also result in apoptosis or premature cellular senescence, both regarded as natural protective barriers to cell immortalization and transformation. In FGFR3-related skeletal dyplasias, oncogenic mutations in the FGFR3 receptor tyrosine kinase cause profound inhibition of cartilage growth resulting in severe dwarfism, although many of the precise mechanisms of FGFR3 action remain unclear. Mutated FGFR3 induces constitutive activation of the ERK pathway in chondrocytes and, remarkably, can also cause both increased proliferation and apoptosis in growing cartilage, depending on the gestational age. Here, we demonstrate that FGFR3 signaling is also capable of inducing premature senescence in chondrocytes, manifested as reversible, ERK-dependent growth arrest accompanied by alteration of cellular shape, loss of the extracellular matrix, upregulation of senescence markers (alpha-GLUCOSIDASE, FIBRONECTIN, CAVEOLIN 1, LAMIN A, SM22alpha and TIMP 1), and induction of senescence-associated beta-GALACTOSIDASE activity. Our data support a model whereby FGFR3 signaling inhibits cartilage growth via exploiting cellular responses originally designed to eliminate cells harboring activated oncogenes.

• MeSH
• apoptóza MeSH
• chondrocyty enzymologie   patologie   MeSH
• extracelulární matrix metabolismus   MeSH
• extracelulárním signálem regulované MAP kinasy metabolismus   MeSH
• fenotyp MeSH
• krysa rodu Rattus MeSH
• onkogeny genetika   MeSH
• proliferace buněk MeSH
• receptor fibroblastových růstových faktorů, typ 3 metabolismus   MeSH
• signální transdukce * MeSH
• stárnutí buněk * MeSH
• tvar buňky MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• extracelulárním signálem regulované MAP kinasy MeSH
• receptor fibroblastových růstových faktorů, typ 3 MeSH

The human fibroblast growth factor (FGF) family contains 22 proteins that regulate a plethora of physiological processes in both developing and adult organism. The mutations in the FGF genes were not known to play role in human disease until the year 2000, when mutations in FGF23 were found to cause hypophosphatemic rickets. Nine years later, seven FGFs have been associated with human disorders. These include FGF3 in Michel aplasia; FGF8 in cleft lip/palate and in hypogonadotropic hypogonadism; FGF9 in carcinoma; FGF10 in the lacrimal/salivary glands aplasia, and lacrimo-auriculo-dento-digital syndrome; FGF14 in spinocerebellar ataxia; FGF20 in Parkinson disease; and FGF23 in tumoral calcinosis and hypophosphatemic rickets. The heterogeneity in the functional consequences of FGF mutations, the modes of inheritance, pattern of involved tissues/organs, and effects in different developmental stages provide fascinating insights into the physiology of the FGF signaling system. We review the current knowledge about the molecular pathology of the FGF family.

• MeSH
• fibroblastové růstové faktory genetika   metabolismus   MeSH
• fibroblastový růstový faktor 23 MeSH
• hypogonadismus genetika   metabolismus   MeSH
• karcinom genetika   metabolismus   MeSH
• lidé MeSH
• mnohočetné abnormality genetika   MeSH
• mutace * MeSH
• rozštěp rtu genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• FGF23 protein, human MeSH Prohlížeč
• fibroblastové růstové faktory MeSH
• fibroblastový růstový faktor 23 MeSH

Activation of fibroblast growth factor receptor 3 (FGFR3) leads to attenuation of cartilage growth. The members of the STAT family of transcription factors are believed to participate in FGFR3 signaling in cartilage, however the molecular mechanism of this action is poorly understood. Here, we demonstrate that a chronic FGF stimulus leads to accumulation of STAT1, 3, 5 and 6, evident in both in vitro chondrocyte model and murine limb explant cultures. Despite the accumulation, both endogenous and cytokine-induced activation of STAT1 and STAT3 is impaired by FGF, as demonstrated by imaging of active STAT nuclear translocation and analyses of STAT activatory phosphorylation and transcriptional activation. Further, we demonstrate that FGF induces expression of CIS, SOCS1 and SOCS3 inhibitors of gp130, a common receptor for the IL6-family of cytokines. Since cytokine-gp130 signaling represents an important positive regulator of cartilage, its inhibition may contribute to the growth-inhibitory effect of FGFR3 in cartilage.

• MeSH
• chondrocyty účinky léků   metabolismus   MeSH
• cytokinový receptor gp130 metabolismus   MeSH
• fibroblastový růstový faktor 2 farmakologie   MeSH
• interferon gama antagonisté a inhibitory   farmakologie   MeSH
• interleukin-6 antagonisté a inhibitory   farmakologie   MeSH
• myši MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• protein SOCS1 MeSH
• protein SOCS3 MeSH
• proteiny SOCS metabolismus   MeSH
• receptor fibroblastových růstových faktorů, typ 3 metabolismus   MeSH
• sekvence nukleotidů MeSH
• signální transdukce MeSH
• transkripční faktor STAT1 antagonisté a inhibitory   metabolismus   MeSH
• transkripční faktor STAT3 antagonisté a inhibitory   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• cytokine inducible SH2-containing protein MeSH Prohlížeč
• cytokinový receptor gp130 MeSH
• fibroblastový růstový faktor 2 MeSH
• interferon gama MeSH
• interleukin-6 MeSH
• protein SOCS1 MeSH
• protein SOCS3 MeSH
• proteiny SOCS MeSH
• receptor fibroblastových růstových faktorů, typ 3 MeSH
• Socs1 protein, mouse MeSH Prohlížeč
• Socs3 protein, mouse MeSH Prohlížeč
• transkripční faktor STAT1 MeSH
• transkripční faktor STAT3 MeSH

Activating mutations in FGFR3 tyrosine kinase cause several forms of human skeletal dysplasia. Although the mechanisms of FGFR3 action in cartilage are not completely understood, it is believed that the STAT1 transcription factor plays a central role in pathogenic FGFR3 signaling. Here, we analyzed STAT1 activation by the N540K, G380R, R248C, Y373C, K650M and K650E-FGFR3 mutants associated with skeletal dysplasias. In a cell-free kinase assay, only K650M and K650E-FGFR3 caused activatory STAT1(Y701) phosphorylation. Similarly, in RCS chondrocytes, HeLa, and 293T cellular environments, only K650M and K650E-FGFR3 caused strong STAT1 activation. Other FGFR3 mutants caused weak (HeLa) or no activation (293T and RCS). This contrasted with ERK MAP kinase activation, which was strongly induced by all six mutants and correlated with the inhibition of proliferation in RCS chondrocytes. Thus the ability to activate STAT1 appears restricted to the K650M and K650E-FGFR3 mutants, which however account for only a small minority of the FGFR3-related skeletal dysplasia cases. Other pathways such as ERK should therefore be considered as central to pathological FGFR3 signaling in cartilage.

• MeSH
• bezbuněčný systém metabolismus   MeSH
• biologické modely MeSH
• CHO buňky MeSH
• chrupavka metabolismus   MeSH
• Cricetulus MeSH
• extracelulárním signálem regulované MAP kinasy metabolismus   MeSH
• fosforylace MeSH
• HeLa buňky MeSH
• kosti a kostní tkáň patologie   MeSH
• křečci praví MeSH
• krysa rodu Rattus MeSH
• kultivované buňky MeSH
• lidé MeSH
• mutantní proteiny fyziologie   MeSH
• receptor fibroblastových růstových faktorů, typ 3 genetika   fyziologie   MeSH
• signální transdukce genetika   fyziologie   MeSH
• transkripční faktor STAT1 analýza   metabolismus   fyziologie   MeSH
• vývojové onemocnění kostí genetika   metabolismus   patologie   MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• extracelulárním signálem regulované MAP kinasy MeSH
• mutantní proteiny MeSH
• receptor fibroblastových růstových faktorů, typ 3 MeSH
• transkripční faktor STAT1 MeSH

OBJECTIVES: This article is to study the role of G(1)/S regulators in differentiation of pluripotent embryonic cells. MATERIALS AND METHODS: We established a P19 embryonal carcinoma cell-based experimental system, which profits from two similar differentiation protocols producing endodermal or neuroectodermal lineages. The levels, mutual interactions, activities, and localization of G(1)/S regulators were analysed with respect to growth and differentiation parameters of the cells. RESULTS AND CONCLUSIONS: We demonstrate that proliferation parameters of differentiating cells correlate with the activity and structure of cyclin A/E-CDK2 but not of cyclin D-CDK4/6-p27 complexes. In an exponentially growing P19 cell population, the cyclin D1-CDK4 complex is detected, which is replaced by cyclin D2/3-CDK4/6-p27 complex following density arrest. During endodermal differentiation kinase-inactive cyclin D2/D3-CDK4-p27 complexes are formed. Neural differentiation specifically induces cyclin D1 at the expense of cyclin D3 and results in predominant formation of cyclin D1/D2-CDK4-p27 complexes. Differentiation is accompanied by cytoplasmic accumulation of cyclin Ds and CDK4/6, which in neural cells are associated with neural outgrowths. Most phenomena found here can be reproduced in mouse embryonic stem cells. In summary, our data demonstrate (i) that individual cyclin D isoforms are utilized in cells lineage specifically, (ii) that fundamental difference in the function of CDK4 and CDK6 exists, and (iii) that cyclin D-CDK4/6 complexes function in the cytoplasm of differentiated cells. Our study unravels another level of complexity in G(1)/S transition-regulating machinery in early embryonic cells.

• MeSH
• biologické modely MeSH
• buněčná diferenciace * MeSH
• buněčný rodokmen * MeSH
• cyklin A metabolismus   MeSH
• cyklin D MeSH
• cyklin E metabolismus   MeSH
• cyklin-dependentní kinasa 4 metabolismus   MeSH
• cyklin-dependentní kinasa 6 metabolismus   MeSH
• cykliny metabolismus   MeSH
• embryo savčí cytologie   metabolismus   MeSH
• embryonální kmenové buňky metabolismus   MeSH
• G1 fáze MeSH
• inhibitor p27 cyklin-dependentní kinasy metabolismus   MeSH
• intracelulární prostor metabolismus   MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• proliferace buněk MeSH
• S fáze MeSH
• transport proteinů MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• CDK4 protein, human MeSH Prohlížeč
• cyklin A MeSH
• cyklin D MeSH
• cyklin E MeSH
• cyklin-dependentní kinasa 4 MeSH
• cyklin-dependentní kinasa 6 MeSH
• cykliny MeSH
• inhibitor p27 cyklin-dependentní kinasy MeSH