scholarly journals Expression of Activated MAP Kinase in Xenopus laevis Embryos: Evaluating the Roles of FGF and Other Signaling Pathways in Early Induction and Patterning

2000 ◽  
Vol 228 (1) ◽  
pp. 41-56 ◽  
Author(s):  
Kristen L. Curran ◽  
Robert M. Grainger
2019 ◽  
Vol 14 (2) ◽  
pp. 196-213
Author(s):  
Patrizia Bonfanti ◽  
Anita Colombo ◽  
Melissa Saibene ◽  
Luisa Fiandra ◽  
Ilaria Armenia ◽  
...  

2016 ◽  
Vol 133 ◽  
pp. 90-96 ◽  
Author(s):  
Marina Isidori ◽  
Concetta Piscitelli ◽  
Chiara Russo ◽  
Marie Smutná ◽  
Luděk Bláha

1995 ◽  
Vol 204 (3) ◽  
pp. 198-202 ◽  
Author(s):  
Peter Wagner ◽  
Michael Hoever ◽  
Katrin Appel ◽  
Walter Kn�chel ◽  
Mathias Montenarh

1997 ◽  
Vol 17 (7) ◽  
pp. 3547-3555 ◽  
Author(s):  
M B Ramocki ◽  
S E Johnson ◽  
M A White ◽  
C L Ashendel ◽  
S F Konieczny ◽  
...  

The ability of basic helix-loop-helix muscle regulatory factors (MRFs), such as MyoD, to convert nonmuscle cells to a myogenic lineage is regulated by numerous growth factor and oncoprotein signaling pathways. Previous studies have shown that H-Ras 12V inhibits differentiation to a skeletal muscle lineage by disrupting MRF function via a mechanism that is independent of the dimerization, DNA binding, and inherent transcriptional activation properties of the proteins. To investigate the intracellular signaling pathway(s) that mediates the inhibition of MRF-induced myogenesis by oncogenic Ras, we tested two transformation-defective H-Ras 12V effector domain variants for their ability to alter terminal differentiation. H-Ras 12V,35S retains the ability to activate the Raf/MEK/mitogen-activated protein (MAP) kinase cascade, whereas H-Ras 12V,40C is unable to interact directly with Raf-1 yet still influences other signaling intermediates, including Rac and Rho. Expression of each H-Ras 12V variant in C3H10T1/2 cells abrogates MyoD-induced activation of the complete myogenic program, suggesting that MAP kinase-dependent and -independent Ras signaling pathways individually block myogenesis in this model system. However, additional studies with constitutively activated Rac1 and RhoA proteins revealed no negative effects on MyoD-induced myogenesis. Similarly, treatment of Ras-inhibited myoblasts with the MEK1 inhibitor PD98059 revealed that elevated MAP kinase activity is not a significant contributor to the H-Ras 12V effect. These data suggest that an additional Ras pathway, distinct from the well-characterized MAP kinase and Rac/Rho pathways known to be important for the transforming function of activated Ras, is primarily responsible for the inhibition of myogenesis by H-Ras 12V.


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