Figure 5.

Proposed model of the lateral assembly of myosin filaments onto myofibrils of mature sarcomeres. (A) The assembly of myosin filaments splits the premyofibrils, rearranges the alpha-actinin to the Z-disk area, and removes alpha-actinins from the A-band area. (B) The alignment of the growing myofibril is affected by the adjacent mature myofibril. The growing myofibril aligns along the mature myofibril, and the Z-disks of a growing myofibril connect and merge with the adjacent Z-disks in the neighboring mature myofibril. The Z-disks become thinner during the maturation of the myofibril as myosin filaments assemble to the myofibril.