title: Characterization of a cAMP-dependent protein kinase catalytic subunit from rainbow trout spermatozoa.
abstract: The cyclic AMP-dependent phosphorylation of proteins is essential for the initiation of sperm motility in salmonid fishes. This study isolated cDNA for the catalytic subunit of a cAMP-dependent protein kinase (PKA-C) from rainbow trout testis. The deduced amino acid sequence shows 75-80% identity to sequences previously reported in other organisms. However, the N-terminal regions of PKA-C from the testis as well as ovary in the trout appear slightly shorter than those from other tissues, suggesting that small PKA-C might be specific to germ cells. An immunofluorescence study using polyclonal antibody against trout testis PKA-C shows that it localizes along sperm flagellum. Furthermore, immunoelectron microscopy revealed that PKA-C is anchored to the outer arm dynein of flagellar axonemes. These results suggest that PKA-C is involved in regulating the flagellar motility of sperm via phosphorylation of a subunit of the outer arm dynein.
authors.affiliation: Misaki Marine Biological Station, Graduate School of Science, The University of Tokyo, Koajiro, Misaki, Miura, Kanagawa 238-0225, Japan. itoh@dmb.med.keio.ac.jp
authors.forename: Atsuko
authors.initials: A
authors.lastname: Itoh
authors.forename: Kazuo
authors.initials: K
authors.lastname: Inaba
authors.forename: Hideki
authors.initials: H
authors.lastname: Ohtake
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Fujinoki
authors.forename: Masaaki
authors.initials: M
authors.lastname: Morisawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020134:Catalytic Domain; D003001:Cloning, Molecular; D017868:Cyclic AMP-Dependent Protein Kinases / Q000032:analysis* / Q000737:chemistry / Q000235:genetics*; D004398:Dyneins / Q000648:ultrastructure; D005407:Flagella / Q000201:enzymology; D008297:Male; D016253:Microscopy, Immunoelectron; D008870:Microtubules / Q000201:enzymology / Q000648:ultrastructure; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss; D021122:Protein Subunits; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013094:Spermatozoa / Q000201:enzymology* / Q000648:ultrastructure; D014018:Tissue Distribution
chemical_list: D021122:Protein Subunits; D017868:Cyclic AMP-Dependent Protein Kinases; D004398:Dyneins