Myosin fragment expression

Zhang, Y., Taylor, M.G. and Bickle, Q.D. (1 998) Schistosoma japonicum myosin cloning, expression and vaccination studies with the homologue of the 5. mansoni myosin fragment lrV-5. Parasite Immunology 20, 583-594. 

Manstein, D.J., Ruppel, K.M., Spudich, J.A. (1989). Expression and characterization of a functional myosin head fragment in Dictyostelium discoideum. Science 246, 656-658. 

Genetic engineering has recently provided a promising approach to the understanding of these functions. A myosin head fragment has been expressed... 

LC20 phosphorylation produces two pronounced effects it promotes the ability of myosin monomers to assemble into filaments, and it markedly increases (100-fold) the ATPase activity of myosin compared to un-phosphorylated filamentous myosin. How unphosphory-lated myosin filaments can remain stable is not certain, but may be related to binding to myosin of independently expressed MLCK fragments containing the myosin binding domain of MLCK. How LC20 phosphorylation increases the ATPase activity so dramatically is still unknown. 

Cardiac troponin complex consists of three parts. Troponin T facilitates contraction, troponin 1 (cTnl) inhibits actin-myosin interactions, and troponin C binds to calcium ions. Troponin I and T are specific to the heart, but cTnT is also expressed by injured skeletal muscle. In the course of cell damage, cardiac troponin is released from myocytes, facilitated by increased membrane permeability that allows smaller troponin fragments to traverse the membrane. Complicating the use of troponin levels is the fact that in cases where there is cardiac injury without cardiac cell membrane disruption, serum troponin level can increase. Also, altered ion homeostasis may not be reflected in troponin levels. 

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