In June 2004, Carna Biosciences and CrystalGenomics, a Korean company, signed an agreement relating to a collaborative effort involving protein kinases. The two companies selected 10 protein kinases, the molecules that control cellular signaling, as potential drug targets. Under the agreement, Carna Biosciences will conduct the expression and purification of the protein kinases, develop the assays, and perform the screening. CrystalGenomics will be responsible for virtual screening of compounds, compound library generation, and x-ray crystallographic analysis. The goal of the collaborative research is to identify drug candidates having a high degree of enzyme selectivity that could potentially be new agents for the treatment of cancer, rheumatoid arthritis and atherosclerosis. The companies plan to license the drug candidates to pharmaceutical companies after their preliminary characterization.