Research Area 1: Molecular basis of phosphotransfer

Project 2: Phosphotransfer by protein kinases

Biochemical Characterization of Microtubule-Associated Serine/Threonine Kinases (MASTKs)

Background and previous work

Protein kinases are key enzymes in the regulation of eukaryotic signal transduction. They alter the biophysical and biochemical properties of target proteins by covalently attaching phosphoryl groups (from ATP). Having studied members of the AGC protein kinase family for over two decades, we extended our studies now to microtubule-associated serine/threonine kinases (MASTKs). MASTKs are multi-domain protein kinases that have been associated with several human disorders such as inflammatory bowel disease and breast cancer. Drop out (dop) is the only Drosophila homolog of human MASTKs. Phenotypic analyses have shown that mutations in dop result in embryonic lethal developmental defects, further emphasizing the essential biological role of MASTKs.

Specific aims

In this project we want to study human and Drosophila MASTKs invitro. We will employ biochemical analyses by means of site directed mutagenesis and will attempt to identify putative substrates. Furthermore, the regulation of MASTKs by autophosphorylation and by upstream kinases / phosphatases will be investigated. The Drosophila MASTK dop will be used as a model in order to achieve a deeper understanding of human MASTK function at the molecular level. This could help to unravel the role of MASTK defects in disease pathogenesis.

Working program

- Detailed description of protein kinase function on a molecular basis employing structural, biochemical and biophysical methods (with all collaboration partners)

- Structural studies on selected members of the protein kinase family (in collaboration with P1)

- Biochemical and phenotypic study of MASTK mutations in D. melanogaster (in collaboration with P4)