The primary focus of our laboratory is Neuronal Cell Biology. We are currently exploring mechanisms of axonal transport and post-translational modification of macromolecules within cells. One problem concerns the role of phosphorylation in controlling the assembly and stabilization of cytoskeletal organelles. We have shown that a microtubule-associated protein normally concentrated in the axon of neurons is a major constituent of pathological inclusions found in the cell bodies of affected neurons in Alzheimer's and other neurodegenerative diseases. The protein appears to be modified in the disease state, and we are currently testing the functional properties of the modified protein. Other studies are concerned with properties of tyrosine kinase systems found in microglia with emphasis on substrates phosphorylated in response to injury.