ABSTRACT
The vesicular glutamate transporter (VGLUT) transports glutamate into pre-synaptic vesicles. Three isoforms of VGLUT have been identified in humans, but their functional differences remain largely unknown. EAT-4 is the only homologue of human VGLUT in C. elegans. Here we report that mutants of eat-4 exhibit hyperforaging behavior and that each of the isoforms of human VGLUT functionally rescues the defects in eat-4 worms.
Subject(s)
Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans/metabolism , Protein Isoforms/metabolism , Receptors, Glutamate/metabolism , Vesicular Glutamate Transport Proteins/metabolism , Amino Acid Sequence , Animals , Animals, Genetically Modified , Caenorhabditis elegans/cytology , Caenorhabditis elegans Proteins/chemistry , Caenorhabditis elegans Proteins/genetics , Humans , Molecular Sequence Data , Protein Isoforms/genetics , Receptors, Glutamate/chemistry , Receptors, Glutamate/genetics , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Sequence Alignment , Vesicular Glutamate Transport Proteins/chemistry , Vesicular Glutamate Transport Proteins/geneticsABSTRACT
Calcineurin is a Ca(2+)-calmodulin-dependent serine/threonine protein phosphatase that has been implicated in various signaling pathways. Here we report the identification and characterization of calcineurin genes in Caenorhabditis elegans (cna-1 and cnb-1), which share high homology with Drosophila and mammalian calcineurin genes. C. elegans calcineurin binds calcium and functions as a heterodimeric protein phosphatase establishing its biochemical conservation in the nematode. Calcineurin is expressed in hypodermal seam cells, body-wall muscle, vulva muscle, neuronal cells, and in sperm and the spermatheca. cnb-1 mutants showed pleiotropic defects including lethargic movement and delayed egg-laying. Interestingly, these characteristic defects resembled phenotypes observed in gain-of-function mutants of unc-43/Ca(2+)-calmodulin-dependent protein kinase II (CaMKII) and goa-1/G(o)-protein alpha-subunit. Double mutants of cnb-1 and unc-43(gf) displayed an apparent synergistic severity of movement and egg-laying defects, suggesting that calcineurin may have an antagonistic role in CaMKII-regulated phosphorylation signaling pathways in C. elegans.
Subject(s)
Caenorhabditis elegans/metabolism , Calcineurin/genetics , Calcineurin/metabolism , Amino Acid Sequence , Animals , Blotting, Northern , Cell Division , Cell Movement , Cloning, Molecular , DNA, Complementary/metabolism , Dose-Response Relationship, Drug , Gene Deletion , Gene Library , Green Fluorescent Proteins , Immunohistochemistry , Luminescent Proteins/metabolism , Microscopy, Fluorescence , Models, Genetic , Molecular Sequence Data , Mutation , Phenotype , Phosphoric Monoester Hydrolases/metabolism , Phosphorylation , Recombinant Fusion Proteins/metabolism , Sequence Homology, Amino Acid , Signal Transduction , Two-Hybrid System TechniquesABSTRACT
In this study, we have isolated a bovine homologue bgl-1 of lethal giant larvae (lgl) tumor suppressor oncogene from bovine brain by RT-PCR using primers designed based on the conserved sequences for lgl family members. The sequence analysis showed that the bgl-1 encodes a 1,036 amino acid polypeptide with the molecular weight of approximately 112 kDa containing a domain characteristic of WD-40 proteins. The amino acid sequence of bgl-1 showed a homology of 98.3 and 87.3% identity to that of mouse and human, respectively. Northern blot analysis showed that bgl-1 was highly expressed in brain, ovary and testis, with moderate expression in liver, uterus, lung and kidney. This suggests that the bgl-1 may play essential roles in each of these organs. The complementation analysis revealed that the bovine bgl-1 partially restored the Na+ tolerance in the absence of yeast lgl homologue, suggesting that bgl-1 is a bovine homologue of the lgl family.