Phosphorylation thick filament regulation

Contraction in amoeboid cells makes use of nonmuscle forms of myosin type II whieh form bipolar thiek filaments in the cytoplasm and in association with the actin filaments [23, 54]. In Dictyostelium, actin filaments form a eortieal shell directly under the plasma membrane, with random orientation of the filaments [132]. Activation of myosin contractile activity by phosphorylation of the myosin light ehain protein results in contraction of the cortical network [54, 110], It is unclear whether this contraetion is uniform throughout the eell or whether there is spatial regulation of the activity. In polarized motile Dictyostelium cells, myosin is concentrated at the rear of the cell [31], which could maintain the polarization, while a myosin heavy chain kinase (which phosphorylates the myosin heavy chain protein and inhibits thick filament formation), is localized at the front of the cell. 

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