Arginine kinases from the marine feather star Tropiometra afra macrodiscus: The first finding of a prenylation signal sequence in metazoan phosphagen kinases.

Two arginine kinase cDNAs (AK1 and AK2) were isolated from the marine feather star Tropiometra afra macrodiscus, and the gene structure (exon/intron organization) of AK1 was determined. The cDNA-derived amino acid sequences and the exon/intron organization of the Tropiometra AK1 gene were homologous to those of a human creatine kinase (CK) as well as the AK of the sea cucumber Stichopus. Phylogenetic analysis also supports the close relationship between human CKs and echinoderm AKs, indicating that the latter AKs evolved from an ancestral CK gene.