The titin protein present in the muscle fibre binds
The titin protein present in the muscle fibre binds the head ends of myosin filaments to the Z-disc Several proteins other than actin and myosin are also present in the muscle. Some of them include: 1. Titin It is the largest known protein It runs between the M line and Z disc and binds the head ends of myosin filaments to the Z disc. It has a tethered poion in the A band , where it is attached to the myosin filament and an elastic poion in the I band. The elastic propey of the titin causes elastic recoil of the sarcomere and prevents it from being overstretched. 2.Nebulin It extends from the Z disc and runs along the full length of each actin filament. It regulates the length of the actin filament. 3. a-actinin It is a component of the Z discs It binds the plus ends of actin filament to this disc. 4. Myomesin It is present in the region of the M line. It maintains the regular lattice arrangement of the myosin filaments in this region. 5. Desmin: It is an intermediate filament characteritic of the muscle. It encircles the myofibrils near the Z disc and binds myofibrils to each other and also to the cell membrane. 6. Dystrophin It is present in the periphery of the muscle fibre, towards the cytoplasmic face of the sarcolemma. It binds to the actin filaments and the glycoprotein complex, consisting of the dystroglycan and sarcoglycan that spans the sarcolemma. Ref: Inderbir Singh's Textbook of Human Histology 8th edition Pgno: 80
The tail ends of actin filaments to Z disc
The tail ends of myosin filaments to the Z disc
The tail end of myosin filaments to M disc
The myofibrils to each other, and also to the cell membrane
General physiology