sentence: Despite the significant progress in identification of numerous actin binding proteins to regulate axon development [ 13 ] , [ 14 ] , [ 15 ] , however , the mechanism of axon formation is still not fully understood.Class X myosin ( myosin X, Myo10 ) , a molecular motor , localizes at the tip of filopodia and other actin-rich peripheral protrusions and is critical for filopodium formation and cell motility [ 16 ] .