Protein kinase C family evolution in jawed vertebrates

Protein kinase C (PKC) was one of the first kinases identified in human cells. It is now known to constitute a family of kinases that respond to diacylglycerol, phosphatidylserine and for some family members, Ca2+. They have a plethora of different functions, such as cell cycle regulation, immune response and memory formation. In mammals, 12 PKC family members have been described, usually divided into 4 different subfamilies. We present here a comprehensive evolutionary analysis of the PKC genes in jawed vertebrates with special focus on the impact of the two tetraploidizations (1R and 2R) before the radiation of jawed vertebrates and the teleost tetraploidization (3R), as illuminated by synteny and paralogon analysis including many neighboring gene families. We conclude that the vertebrate predecessor had five PKC genes, as tunicates and lancelets still do, and that the PKC family should therefore ideally be organized into five subfamilies. The 1R and 2R events led to a total of 12 genes distributed among these five subfamilies. All 12 genes are still present in some of the major lineages of jawed vertebrates, including mammals, whereas birds and cartilaginous fishes have lost one member. The 3R event added another nine genes in teleosts, bringing the total to 21 genes. The zebrafish, a common experimental model animal, has retained 19. We have found no independent gene duplications. Thus, the genome doublings completely account for the complexity of this gene family in jawed vertebrates and have thereby had a huge impact on their evolution.

Automated summary

PKC, one of the earliest identified kinases in human cells, forms a family of kinases that respond to various signaling molecules with diverse functions. Evolutionary analysis reveals a vertebrate predecessor with five PKC genes, leading to a total of 21 genes in jawed vertebrates due to genome doublings. The genome duplications account for the complexity of the PKC gene family in jawed vertebrates and greatly impact their evolution.