Caenorhabditis elegans contains two distinct acid sphingomyelinases Journal Article
| Authors: | Lin, X.; Hengartner, M. O.; Kolesnick, R. |
| Article Title: | Caenorhabditis elegans contains two distinct acid sphingomyelinases |
| Abstract: | Mounting evidence supports a role for acid sphingomyelinase (ASM) in cellular stress signaling. Only murine and human sphingomyelinases have been defined at the molecular level. These enzymes are the products of a conserved gene and at the amino acid level share 82% identity. In this study, we show that the nematode Caenorhabditis elegans possesses two ASMs, termed ASM-1 and ASM-2 encoded by two distinct genes, but lacks detectable neutral sphingomyelinase activity. The C. elegans ASMs are about 30% identical with each other and with the human and murine enzymes. The conserved regions include a saposin-like domain, proline-rich domain, and a putative signal peptide. In addition, 16 cysteines distributed throughout the molecules, and selected glycosylation sites, are conserved. The expression of these genes in C. elegans is regulated during development. Asm-1 is preferentially expressed in the embryo, whereas asm-2 is predominantly expressed in postembryonic stages. When transfected as Flag-tagged proteins into COS-7 cells, ASM-1 is found almost entirely in a secreted form whereas only 20% of ASM-2 is secreted. Only the secreted forms display enzymatic activity. Furthermore, ASM-2 requires addition of Zn2+ to be fully active, whereas ASM-1 is active in the absence of cation. C. elegans is the first organism to display two ASMs. This finding suggests the existence of an ASM gene family. |
| Keywords: | signal transduction; protein expression; nonhuman; animal cell; animals; gene expression; embryo development; transfection; cos cells; animalia; evolution, molecular; cloning, molecular; amino acid sequence; conserved sequence; molecular sequence data; sequence homology, amino acid; rna, messenger; murinae; caenorhabditis elegans; zinc; nematoda; sphingomyelin phosphodiesterase; sequence analysis, dna; invertebrata; cations; priority journal; article |
| Journal Title: | Journal of Biological Chemistry |
| Volume: | 273 |
| Issue: | 23 |
| ISSN: | 0021-9258 |
| Publisher: | American Society for Biochemistry and Molecular Biology |
| Date Published: | 1998-06-05 |
| Start Page: | 14374 |
| End Page: | 14379 |
| Language: | English |
| DOI: | 10.1074/jbc.273.23.14374 |
| PUBMED: | 9603947 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | Article -- Export Date: 12 December 2016 -- Source: Scopus |
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