since actin , myosin , and in certain systems , tropomyosin have now been described in nonmuscle cells , it is not surprising that most of the current models of nonmuscle cell motility are simplified versions of myofibril contraction ( see huxley , 1973 ; pollard and weihing , 1974 ; spudich , 1974 ) .
C0007634
cells
C0007608
cell motility