Figure 9. Schematic representation of YAP and NOTCH signaling pathways in normal contracting muscles and paralyzed muscles.

• (A) In contracting muscles, nuclear YAP (green myonuclei) and YAP target gene transcripts (green) are present in post-mitotic muscle fibers. YAP positively regulatesJAG2transcription upon muscle contraction. Ligand-dependent NOTCH activation regulates the muscle progenitor pool, by preventing muscle progenitors to differentiate. (B) In paralyzed muscles, nuclear YAP, YAP target genes andJAG2transcripts are lost in post-mitotic muscle fibers. The absence of the NOTCH ligand JAG2 in fibers, due to the loss of mechanical signals, induces a NOTCH loss-of-function phenotype i.e. a diminution in the number of muscle progenitors and a shift toward differentiation, in a non-cell autonomous manner.

• eLife
• DOI: 10.7554/elife.15593.017