Classification and Domain Analysis of Protein Kinases in Hominids

A comparative analysis of protein kinases encoded in the human genome and those of the closest evolutionary relatives such as chimpanzee, gorilla and orangutan is made in the present study. Sequence comparisons of humans with their closest lineages are of considerable interest in order to understand the ambulatory mechanism behind the evolutionary relationship of apes. A total of 499, 478, 468 and 470 protein kinases from human, chimpanzee, gorilla and orangutan genomes respectively, which include both eukaryotic protein kinases and atypical protein kinases were analysed. Classification of their groups and families reveals the presence of three highly populated protein kinase families, namely STE20, CAMKL and CDK in the four genomes and also few unique protein kinases, namely ADCK2, ADCK3, BCKDK, CDK11A, C9orf96, PDK1, PDK2 and TAF1 in humans. Domain organization of each of the protein kinases in the four genomes shows the presence of frequently occurring domains such as SH2 domain, immunoglobulin-I set domain, phorbol esters/diacylglycerol binding domain (C1 domain), and SH3 domain in all four genomes, and unusual domain architectures for few human atypical protein kinases such as BCKDK, PDK1 and PDK2. This hominid-based comparative study will provide valuable insights into the similarities and differences between humans and three other non-human apes in kinome-level ranking and functional aspects and a base for experimental analysis on hominids in order to enhance our understanding on their specific biological roles.