title: Two membrane-associated tyrosine phosphatase homologs potentiate C. elegans AKT-1/PKB signaling.
abstract: Akt/protein kinase B (PKB) functions in conserved signaling cascades that regulate growth and metabolism. In humans, Akt/PKB is dysregulated in diabetes and cancer; in Caenorhabditis elegans, Akt/PKB functions in an insulin-like signaling pathway to regulate larval development. To identify molecules that modulate C. elegans Akt/PKB signaling, we performed a genetic screen for enhancers of the akt-1 mutant phenotype (eak). We report the analysis of three eak genes. eak-6 and eak-5/sdf-9 encode protein tyrosine phosphatase homologs; eak-4 encodes a novel protein with an N-myristoylation signal. All three genes are expressed primarily in the two endocrine XXX cells, and their predicted gene products localize to the plasma membrane. Genetic evidence indicates that these proteins function in parallel to AKT-1 to inhibit the FoxO transcription factor DAF-16. These results define two membrane-associated protein tyrosine phosphatase homologs that may potentiate C. elegans Akt/PKB signaling by cell autonomous and cell nonautonomous mechanisms. Similar molecules may modulate Akt/PKB signaling in human endocrine tissues.
authors.affiliation: Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Hu
authors.forename: Jinling
authors.initials: J
authors.lastname: Xu
authors.forename: Gary
authors.initials: G
authors.lastname: Ruvkun
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism; D005786:Gene Expression Regulation; D005821:Genetic Techniques; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
chemical_list: D029742:Caenorhabditis elegans Proteins; D051057:Proto-Oncogene Proteins c-akt; C512524:EAK-4 protein, C elegans; C512525:EAK-6 protein, C elegans; D017027:Protein Tyrosine Phosphatases