Fig. 8
From: The MuSK-BMP pathway maintains myofiber size in slow muscle through regulation of Akt-mTOR signaling
A model for MuSK-BMP regulation of muscle fiber size in slow muscle. A MuSK containing the Ig3 domain binds BMP and promotes BMP signaling. B In soleus, MuSK is expressed at the sarcolemma and regulates myofiber size via the Akt-mTOR pathway. C MuSK is not detected in the sarcolemma in fast muscles (e.g., TA, EDL, STM). Note that MuSK is expressed at the NMJ of all muscles. We propose that MuSK-BMP signaling in the sarcolemma selectively regulates myofiber size in slow muscle by controlling the IGF1-Akt-mTOR pathway