14-3-3 links microtubules, rac small GTPases and myosin II dynamics

Using Dictyostelium, we identified a pathway in which the dimeric acidic protein 14-3-3 acts genetically between microtubules, racE and myosin II to control cell shape, cortical tension, and cytokinesis.  In this context, 14-3-3 requires GTP and racE for cortical association, controls the extent of microtubule-cortex interactions, and binds myosin II heavy chain, controlling its assembly into bipolar thick filaments.  This first study was simplified by using Dictyostelium cells, which only has one myosin II and one 14-3-3 protein and was presented in Zhou et al. Curr. Biol. 2010.  

Humans have three nonmuscle myosin II and seven 14-3-3 proteins.  We expressed and purified all 10 proteins and discovered that the 14-3-3s can also modulate human nonmuscle myosin II assembly, particularly myosin IIB.  The study of the human proteins was presented in West-Foyle et al. 2018