Molecular evolution and functional characterization of PKC-α-like in Lamprey

Protein kinase C-α (PKC-α) is a serine/threonine protein kinase categorized within the lipid-regulated PKC family. Despite considerable research on PKC-α in various vertebrates, information about its presence and characteristics in lampreys-among the few extant jawed vertebrates and the most primitive-remains limited. In this study, we report the first identification of a PKC-α-like gene in lamprey by successfully cloning its coding region, composed of 1683 base pairs that encode 560 amino acids, from the constructed cDNA library of Lampetrajaponica. Sequence analysis demonstrated a high degree of homology between the PKC-α-like sequence in lamprey and those in other vertebrates. Phylogenetic analysis indicated that lamprey PKC-α-like occupies an intermediate position between vertebrates and invertebrates, supporting the principles of species evolution. Gene structure analysis revealed low conservation throughout evolution, possibly due to events like chromosomal rearrangements or homologous recombination which may have caused significant changes in gene arrangement patterns. Additionally, we generated polyclonal antibody against PKC-α-like and investigated its tissue distribution in Lampetrajaponica. Our results demonstrated widespread expression of PKC-α-like across all tissues with varying mRNA expression levels in response to different pathogenic stimuli. Specifically, PKC-α-like expression was consistently up-regulated in response to polyinosine-polycytidylic acid (Poly (I:C)) stimulation, especially in immune-related tissues. Furthermore, we confirmed that PKC-α-like is primarily localized in the cytoplasm of lamprey cells. Moreover, our findings indicate that PKC-α-like promotes cell proliferation, prompting us to undertake a preliminary investigation of the underlying molecular mechanisms. In summary, this study establishes a theoretical foundation for further exploration of the evolutionary process of PKC-α and its role in cell proliferation mechanisms.