Polypeptides capable of regulating signal transduction, which preferably exhibit kinase activity, or antibodies against such polypeptides that inhibit the interaction of these polypeptides with other mediators of signal transduction, may be used in the identification, prevention or treatment of disease, preferably cardiac disease, in mammalian hosts. In addition, these polypeptides can facilitate the identification or isolation of additional mediators of signal transduction associated with disease, preferably cardiac disease, which in turn may also be used in the identification, prevention or treatment of disease, preferably cardiac disease, in mammals.