Characterization of myosin V from PC12 cells

PC12 cell line is a cellular model to study neurite outgrowth and neurotran smitter release mechanisms. Molecular motors may be involved in these respo nses and myosin V could be a candidate to mediate these effects. Overlay ex periments using [I-125]-calmodulin showed that PC12 cells possess several c almodulin-binding proteins, some of them around 190-210 kDa. Western blots using affinity purified polyclonal antibodies raised against chicken brain myosin V revealed a component of 190 kDa, a molecular mass typical of myosi n V. Furthermore, Northern blots using a myosin V probe also detected a tra nscript of around 12 kbp. Immunofluorescence cytochemistry demonstrated the localization of myosin V throughout the cytoplasm, in the neurites, growth cone tips, and with an intense asymmetrical perinuclear labeling. Western blot analyses of PC12 cellular extracts after FGF-2 and/or dibutyryl cAMP t reatment revealed variations between myosin V and myosin II expression duri ng neuronal differentiation. These results demonstrated the presence of myo sin V in PC12 cells and also suggest a role for this motor molecule in the neuronal differentiation response in PC12 cells. (C) 1999 Academic Press.