Scaffold proteins assemble vanous signaling molecules into a signalosome and activate signal

transduction cascade. These proteins thus provide platforms for receptors, kinases, phosphatases

and other effectors into a functional modules (Good et al., 2011). Scaffold proteins are thus key

components ofsignaling networks. Among various domain structures in scaffolding proteins, one

commonly found is WD40 repeat. Proteins harboring this domain often act as signaling scaffold in

which the WD40 repeat domain form a beta propeller structure for assembling signaling molecules.