Protein kinases are a large family of proteins which are intimately involved in the genesis and behavior of cancer cells. The data and information about protein kinases domain is spread across several heterogeneous resources and most of these resources are storing data in different formats following different schema. Protein kinase ontology has been developed to capture, integrate and represent sequence, structure, function, motif, pathway and disease information on protein kinases. Protein kinase ontology's population system does this by automatically extracting information from diverse sources and then integrating data to automatically populate knowledge in the ontology. This focused ontology has been further used in several tasks using the huge domain knowledge weaved inside it.