HomoKinase: A Curated Database of Human Protein Kinases

HomoKinase database is a comprehensive collection of curated human protein kinases and their relevant biological information. The entries in the database are curated by three criteria: HGNC approval, gene ontology-based biological process (protein phosphorylation), and molecular function (ATP binding and kinase activity). For a given query protein kinase name, the database provides its official symbol, full name, other known aliases, amino acid sequences, functional domain, gene ontology, pathways assignments, and drug compounds. In addition, as a search tool, it enables the retrieval of similar protein kinases with specific family, subfamily, group, and domain combinations and tabulates the information. The present version contains 498 curated human protein kinases and links to other popular databases. 1. Introduction In human genome, the protein kinase is one of the largest recognized protein families which regulate multiple biological processes by posttranslational phosphorylation of serine, threonine, and tyrosine residues [1]. Human genome contains 500 protein kinase genes that constitute about 2% of all genes [2]. Approximately 2000 protein kinases are encoded by human genome. Protein kinases and phosphatases play an important role in regulating and coordinating aspects of metabolism, cell growth, cell motility, cell differentiation and cell division, and signaling pathways involved in normal development and disease [3]. In human genome, 30% to 50% of proteins may undergo phosphorylation; therefore, improper functioning of kinase may lead to various human diseases [4]. Turning on and off of protein kinases and phosphatases maintains the functions of the cellular life in a systematic manner. Further, protein kinases are involved in regulation of many processes, so they are linked to many diseases and act as target for drug design. Protein kinases are the group of enzymes that share conserved catalytic domains involved in stimulating catalytic activity of enzymes and act as ATP binding sites. This result the need and availability of databases specific to protein kinases. There are many databases for protein kinases present, which include human protein kinases information as well [2, 5, 6]. For example, KinBase [2] contains manually curated kinomes based on Hanks and Hunter classification for nine genomes including humans. KinG [5] contains protein kinases entries for 40 genomes that have been classified by kinome-based sequence search methods. KinWeb [6] is a specific collection of protein kinases encoded in the human genome, and the classification