The molecular scaffold, K protein, is a heterogenous ribonucleoprotein that interacts with DNA, RNA, and a variety of proteins involved in regulating transcription, RNA processing, and translation. Ostrowski et al. demonstrated that the interaction of K protein with tyrosine kinases, Lck and Src, the protooncogene Vav, phospholipase C γ, and RNA were all regulated by the phosphorylation state of the K protein scaffold. Binding and phosphorylation of K by the kinases, as well as binding of Vav and RNA to phosphorylated and unphosphorylated K protein, were measured in vitro. Furthermore, the phosphorylation of K and the interaction of K protein with its partners in vivo was regulated by oxidative stress. The authors suggest that K protein serves as scaffold, that can be regulated, to organize cellular responses to extracellular signals.
Ostrowski, J., Schullery, D.S., Denisenko, O.N., Higaki, Y., Watts, J., Aebersold, R., Stempka, L., Gschwendt, M., and Bomsztyk, K. (2000) Role of tyrosine phosphorylation in the regulation of the interaction of heterogenous nuclear ribonucleoprotein K protein with its protein and RNA partners. J. Biol. Chem. 275: 3619-3628. [Abstract] [Full Text]