... consisting of four copies of foursubunits, a, b, c and d. The a and b subunits are regu-latory and are the sites of phosphorylation and meta-bolite binding and are also regulated by the binding of ... II and IV (CaMKI, CaMKII and CaMKIV, respectively), CaM kinase kinase (CaMKK),titin kinase, and death associated kinase [4]. Structural studies on CaMKI [5], titin kinase [6] and twitchin kinase ... substrate binding sites. In the case of the titin and twitchinkinases, the autoinhibitory sequence acts as a pseudo-substrate, occluding ATP binding and preventingprotein substrates from binding...