High impact information on Fgfr4

• FGFR1 and FGFR4 were shown to be expressed at a high level during early pancreatic development before embryonic day 16, their levels of expression decreasing thereafter [1].
• Contrary to its weak mitogenic activity, FGFR4 effectively mediates the inhibition of myogenic differentiation in L6E9 cells and also suppresses the expression of the myogenic regulatory protein myogenin [2].
• We compared the mitogenic and signaling pathways of three Fibroblast Growth Factor Receptors (FGFRs), FGFR1, KGFR and FGFR4 in the same cell line [2].
• Taken together, our results suggest that the signaling mechanism of FGFR4 differs from that of FGFR1 and KGFR, and that the primary role of FGFR4 in myoblasts may be the maintenance of their non differentiated state [2].
• FGFR4 was localized mostly to maturing nephron structures and was not detected in nephrogenic mesenchyme, mesenchymal condensates, or developing interstitium [3].

Biological context of Fgfr4

• Northern blot hybridization revealed that flg and bek mRNAs were detectable during all stages except a diestrus stage, whereas FGFR-3 and FGFR-4 mRNAs were almost undetectable throughout the cycles [4].
• The unique localization patterns of FGF6 and FGFR4 may reflect specific roles for these members of the FGF signaling complex during myogenesis in adult skeletal muscle [5].
• The gene expression of four fibroblast growth factor receptors (flg, bek, FGFR-3, and FGFR-4) in rat ovary cells was studied [4].
• We show that the PAC1 sublines that undergo a more robust transition into the skeletal muscle phenotype also express significantly higher levels of the insulin-like growth factor (IGF1 and IGF2) genes and of FGF receptor 4 (FGFR4) gene [6].

Anatomical context of Fgfr4

• Since FGFR4 is expressed in myoblasts in vivo, we examined whether this receptor can function in the differentiation pathway of myoblasts [2].
• FGFR1 and FGFR2 were also expressed in muscle-derived fibroblasts, but FGFR4 and FGFR3 were not [7].
• FGFR-3 and FGFR-4 were not expressed in dorsal root ganglia [8].
• In the adult testis epithelium, Sertoli cells were immunoreactive for FGFR-4, and germ cells were immunoreactive for all four FGFRs, with specific receptors localized to specific stages of germ cell development [9].
• The present finding indicates that FGFR-4 has a function specific to the medial habenular nucleus [10].

Associations of Fgfr4 with chemical compounds

• FGFs exert their actions through tyrosine kinase receptors, FGFRs, which are encoded by four FGFR genes (FGFR1 through FGFR4) [3].

Co-localisations of Fgfr4

• FGFR-4 mRNA was colocalized with choline acetyltransferase mRNA to a high degree (more than 90%), indicating that FGFR-4 mRNA-expressed cells are cholinergic neurons [11].

Regulatory relationships of Fgfr4

• This led to a shift in the ratio of FGFR1 to FGFR4 in the FGF-treated cultures which may explain the ability of satellite cells to differentiate under the influence of aFGF [12].

Other interactions of Fgfr4

• We also used RT-PCR to analyze the expression patterns of the four tyrosine kinase FGF receptors (FGFR1-FGFR4) and of the HGF receptor (c-met) in the myofiber cultures [5].
• The temporal sequence of FGF-5 mRNA expression was similar to that of FGFR-4 mRNA expression [13].
• Using reverse transcriptase-polymerase chain reaction (RT-PCR), we found that mRNAs for FGFR-1 IIIb and IIIc, FGFR-2 IIIc, FGFR-3 IIIc and FGFR-4 were expressed in foetal, immature and adult testes [14].
• CONCLUSION: This result suggests that CsA has an alleviated effect on TAA-induced liver injury by increasing the multidrug resistance P-glycoprotein and could be through the regulation of TGFbeta-R1 and FGFR4 [15].

Analytical, diagnostic and therapeutic context of Fgfr4

• Northern blot analysis of adult rat tissues demonstrated that a 3.1-kb mRNA encoding FGFR4 is detectable only in the lung and kidney [16].
• Fibroblast growth factor receptor 4 (FGFR4), Frizzled 9 (Fz9), and SRY box-containing gene 2 (Sox2) as assessed by immunocytochemistry and in situ hybridization are markers that appear to distinguish NSCs from other precursor cells [17].
• The relative levels of glomerular expression of these isoforms were determined using a semiquantitative RT-PCR assay using primers designed against three transmembrane regions; FGFR1 (100%); FGFR2 (0.1%); and FGFR4 (6%) [18].
• Only FGFR4 was expressed at a higher level in the myofibers but not the connective tissue cell cultures [5].
• FGFR4 was also expressed at a higher level in satellite cells compared to the nonmyogenic cells when the two cell populations were released from the muscle tissue and fractionated by Percoll density centrifugation [5].

References