Fig. 8

Fig. 8 Hhip regulates muscle development. (A) Hhip functions to sequester Hh and modulate localization of Smo. Hhip together with Ptc sequesters Hh and then Hhip internalizes together with Smo into endosomes. This function allows adaxial cells to accumulate high levels of Hh while preventing movement of Hh to more lateral cells. (B) Inhibition of Hhip allows Hh activity to spread to cells lateral to adaxial cells. Increased Hh activity allows lateral cells to express myod (green, left panel) and to development subsequently into extra muscle pioneer cells and slow muscle cells (green, right panel). Left panels; dark green, cells responding to Hh. Right panels; dark green, muscle pioneer cells; green, slow muscle cells; pink; fast muscle cells.