UC Berkeley

Cellular signaling is controlled by many different processes which make up a signaling cascade. The timing and spatial organization of the steps within a signaling cascade are crucial to a cell’s development and proliferation. In this work I explore the structural and biochemical processes that mediate activity of two important signaling proteins: Bruton’s tyrosine kinase (Btk) and Ras. In the case of Btk I explore the mechanistic details of dimerization of its lipid binding domain and how this corresponds to signaling by Btk in the cell. In addition, I characterize the interaction of growth factor receptor-bound protein 2 (Grb2) with Btk and outline a novel role for Grb2 in Btk signaling. Finally, I explore the specificity constraints on Btk substrates as compared to an upstream kinase, Spleen tyrosine kinase (Syk). In the case of Ras, this work explores how stability of the protein, both local conformational stability and global stability, impact the activity and structure of the enzyme. This work is carried out using a variety of structural, biochemical, and biophysical methods, from molecular dynamics and nuclear magnetic resonance (NMR) to reconstitution of signaling proteins on supported lipid bilayers.