Shear stress modulates the action of the 88 K protein-actin complex on actin polymerization

An actin-regulatory protein, 88 K protein-actin complex (88 K-actin complex) isolated from porcine brain, increases the rate of actin polymerization as measured by viscometry which gives rise to shearing stresses. In contrast, when measured by the optical absorption method without solvent flow, the complex does not promote actin polymerization but inhibits both the initial rate and final extent of polymerization. These results suggest that shearing stresses are capable of modulating association of actin with the 88 K-actin complex.