Skip to main content
Fig. 4 | Skeletal Muscle

Fig. 4

From: The beneficial role of proteolysis in skeletal muscle growth and stress adaptation

Fig. 4

The role of caspases in skeletal myoblast differentiation. Caspase 3 has a multifaceted role in regulating myogenesis. It is responsible for the proteolytic cleavage of the transcription factor Pax7, which maintains satellite cells in their stem cell niche and prevents myoblast differentiation. Moreover, caspase 3 cleaves the promyogenic kinases MST1, HIPK2, and NEK5 to promote myogenesis. The posttranscriptional regulator, HuR, is also cleaved by caspase 3 and is necessary for muscle fiber formation. Additionally, preliminary evidence (unpublished) suggests that the myogenic differentiation program appears to rely on the caspase-mediated cleavage of chromatin remodeling proteins to increase DNA accessibility for CAD (activated by caspase 3 cleavage of ICAD), which produces DNA strand breaks that are critical to regulating myogenic gene expression. For instance, CAD cleavage of the p21 promoter stimulates p21 expression, which is essential for cell cycle arrest and terminal differentiation. The CAD-derived DNA strand breaks require rapid resolution, which is mediated by the base excision repair protein XRCC1. This mending of DNA strand breaks is necessary to stabilize the genome and ensure the fidelity of the myogenic differentiation program

Back to article page