Cbl-mediated Negative Regulation of the Syk Tyrosine Kinase

Abstract

The proto-oncogene product Cbl has emerged as a potential negative regulator of the Syk tyrosine kinase; however, the nature of physical interactions between Cbl and Syk that are critical for this negative regulation remains unclear. Here we show that the phosphoty-rosine-binding (PTB) domain within the N-terminal transforming region of Cbl (Cbl-N) binds to phosphoryl-ated Tyr 323 in the linker region between the Src homol-ogy 2 and kinase domains of Syk, confirming recent results by another laboratory using the yeast two-hybrid approach (Deckert