Conditional regulation of a ROCK-estrogen receptor fusion protein

The Rho-associated kinases ROCK I and ROCK II are serine/threonine kinases that play central and critical roles in regulating the actin cytoskeleton. Activation of ROCK proteins contributes positively to the phosphorylation of myosin II light chains (MLC), myosin ATPase activity, stabilization of filamentous actin, and coupling of the actin-myosin filaments to the plasma membrane, thereby leading to the increased actin-myosin force generation and contractility. We have constructed a conditionally-activated form of ROCK II (called ROCKER) by fusing the ROCK II kinase domain to the estrogen receptor hormone-binding domain. In this chapter, we describe the construction and characterization of this regulatable ROCKER fusion protein.