BINDING OF CDK9 TO TRAF2

CDK9 has been recently shown to have increased kinase activity in diff erentiated cells in culture and a differentiated tissue-specific expre ssion in the developing mouse. In order to identify factors that contr ibute to CDK9's differentiation-specific function, we screened a mouse embryonic library in the yeast two-hybrid system and found a tumor ne crosis factor signal transducer, TRAF2, to be an interacting protein. CDK9 interacts with a conserved domain in the TRAF-C region of TRAF2, a motif that is known to bind other kinases involved in TRAF-mediated signaling. Endogenous interaction between the two proteins appears to be specific to differentiated tissue. TRAF2-mediated signaling may inc orporate additional kinases to signal cell survival in myotubes, a cel l type that is severely affected in TRAF2 knockout mice. (C) 1998 Wile y-Liss, Inc.