Messenger ribonucleic acid encoding an apparent isoform of phosphorylase kinase catalytic subunit is abundant in the adult testis.
The complete amino acid sequence for a novel member of the protein kinase family was deduced from the nucleotide sequence of a cloned human cDNA. This putative protein kinase, given the preliminary designation "PSK-C3," is similar in primary structure to phosphorylase kinase catalytic subunit (PhK-gamma) isolated from rabbit skeletal muscle. The level of similarity does not appear sufficient, however, to suggest that PSK-C3 represents the human homolog of skeletal muscle PhK-gamma. Rather, it seems likely that PSK-C3 is a novel PhK-gamma isoform. From a cross-species Northern hybridization experiment using adult rat tissue RNA, a transcript homologous to PSK-C3 was found to be abundant in the testis but could not be detected in any of 12 other tissues tested, including skeletal muscle, liver, and ovary. Increasing levels of PSK-C3 mRNA in the testis correlate with postnatal testicular development, suggesting possible hormonal regulation of gene transcription. Energy released by glycogeneolysis in the testis may help fuel the process of spermatogenesis.
Hanks
S K
SK
Molecular Biology Laboratory, Salk Institute for Biological Studies, San Diego, California 92138.
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000494:pharmacology; D002147:Calmodulin / Q000494:pharmacology; D002460:Cell Line; D015342:DNA Probes; D005260:Female; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009132:Muscles / Q000201:enzymology; D009693:Nucleic Acid Hybridization; D010764:Phosphorylase Kinase / Q000235:genetics*; D011494:Protein Kinases / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis*; D011817:Rabbits; D051381:Rats; D012689:Sequence Homology, Nucleic Acid; D013737:Testis / Q000201:enzymology* / Q000254:growth & development; D014158:Transcription, Genetic
D002147:Calmodulin; D015342:DNA Probes; D012333:RNA, Messenger; D011494:Protein Kinases; D010764:Phosphorylase Kinase; D002118:Calcium