title: Evolution of the cytoplasmic and mitochondrial phosphagen kinases unique to annelid groups.
abstract: Creatine kinase (CK) is a member of a group of phosphoryl transfer enzymes called phosphagen kinases that play a key role in cellular energy transactions in animals. Three CK isoform gene families are known-cytoplasmic CK (CK), flagellar CK (fCK), and mitochondrial CK (MiCK). Each of the isoforms has a unique gene structure (intron/exon organization). A broad array of other phosphagen kinases is present in animals. Some of these enzymes are found only in annelids and closely related groups including glyocyamine kinase (GK), lombricine kinase (LK), taurocyamine kinase (TK), and a unique arginine kinase (AK) restricted to annelids. Phylogenetic analyses of these annelid phosphagen kinases indicate that they appear to have evolved from a CK-like ancestor. To gain a greater understanding of the relationship of the CK isoforms to the annelid enzymes, we have determined the intron/exon organization of the genes for the following phosphagen kinases: Eisenia LK, Sabellastarte AK, and Arenicola mitochondrial TK (MiTK). Analysis of genomic database for the polychaete Capitella sp. yielded two putative LK genes [cytoplasmic LK and mitochondrial LK (MiLK)]. The intron/exon organization of these genes was compared with available data for cytoplasmic and mitochondrial CKs, and an annelid GK. Surprisingly, these annelid genes, irrespective of whether they are cytoplasmic (LK, AK, and GK) or mitochondrial (MiTK and MiLK), had the same 8-intron/9-exon organization and were strikingly similar to MiCK genes sharing seven of eight splice junctions. These results support the view that the MiCK gene is basal and ancestral to the phosphagen kinases unique to annelids.
authors.affiliation: Laboratory of Biochemistry, Kochi University, Kochi, 780-8520, Japan.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Tanaka
authors.forename: Kouji
authors.initials: K
authors.lastname: Uda
authors.forename: Mayumi
authors.initials: M
authors.lastname: Shimada
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Takahashi
authors.forename: Shinobu
authors.initials: S
authors.lastname: Gamou
authors.forename: W Ross
authors.initials: WR
authors.lastname: Ellington
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Suzuki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003593:Cytoplasm / Q000201:enzymology*; D019143:Evolution, Molecular; D005091:Exons / Q000235:genetics; D006801:Humans; D007438:Introns / Q000235:genetics; D008928:Mitochondria / Q000201:enzymology*; D008969:Molecular Sequence Data; D010770:Phosphotransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D011077:Polychaeta / Q000201:enzymology* / Q000235:genetics*; D016415:Sequence Alignment
chemical_list: D010770:Phosphotransferases