De novo Design and Engineering of Soluble Artificial Kinase Receptor Proteins

A major class of proteins associated with cancer are receptor tyrosine kinases (RTKs), which are involved in molecular signaling related to cell growth and proliferation. RTKs are composed of an integral membrane protein domain that is embedded in the membrane and a cytosolic (soluble) kinase domain. The cytosolic kinase domain becomes activated upon dimerization mediated by the integral membrane domain upon binding to biosignaling molecules (hormones). Drug therapies targeting the RTKs have largely focused on designing molecules that interact with the integral membrane domain, which binds to the signaling molecules, but have largely overlooked the kinase domain. Developing drugs to the kinase domain is difficult since the RTK protein is insoluble due to the presence of the integral membrane portion and removal of the protein from the membrane for studying drug binding can lead to denaturation and inactivation of the protein. The research presented here looks at developing artificial kinase receptors by replacing the integral membrane domain with soluble coiled coil forming peptides that can mimic the normal function of the integral membrane domain, i.e. dimerization, but produce a soluble artificial kinase receptor fusion protein mimic that can be used in drug screening assays to discover new RTK kinase domain inhibitors.