Yap regulates mitochondrial structural remodeling during myoblast differentiation

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• The Yes-associated protein (Yap) is a key coactivator in the Hippo pathway, regulating cell proliferation and tissue growth.
• The role of Yap in myoblast differentiation, a critical process for muscle development, is not fully understood.
• Mitochondrial dynamics, regulated by proteins like dynamin-related protein 1 (Drp1) and mitofusion 2 (Mfn2), are essential for myoblast differentiation.

Purpose of the Study:

• To investigate the interaction between the Hippo/Yap pathway and mitochondrial proteins Mfn2 and Drp1 during myoblast differentiation.
• To elucidate the role of Yap in regulating mitochondrial fission and fusion events in differentiating myoblasts.
• To understand how Hippo/Yap pathway inactivation influences mitochondrial morphology and function in muscle precursor cells.

Main Methods:

• Western blotting to assess the phosphorylation status and protein levels of key Hippo pathway components (Mst1/2, Lats1, Yap) and mitochondrial proteins (Drp1, Mfn2).
• Immunofluorescence microscopy to observe Yap translocation and mitochondrial morphology (fission/fusion).
• Experimental manipulation of Yap expression or activity to determine its effect on myoblast differentiation and mitochondrial dynamics.

Main Results:

• Hippo/Yap pathway inactivation, indicated by decreased phosphorylation ratios, occurred early in myoblast differentiation.
• Inactivation led to Yap translocation to the nucleus, increased Drp1 protein content, and promoted mitochondrial fission.
• Yap downregulation inhibited myoblast differentiation, reduced Drp1 levels, caused mitochondrial elongation, and impaired mitochondrial membrane potential.

Conclusions:

• Inactivation of the Hippo/Yap pathway is a key event in early myoblast differentiation.
• The Hippo/Yap pathway regulates myoblast differentiation through modulation of mitochondrial fission, primarily by controlling Drp1 protein levels.
• Targeting the Hippo/Yap pathway and its downstream effectors like Drp1 may offer new strategies for modulating muscle development and regeneration.