Enzymes
| UniProtKB help_outline | 3 proteins |
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- Name help_outline N-(tetracosanoyl)-sphing-4-enine-1-phosphocholine Identifier CHEBI:83360 Charge 0 Formula C47H95N2O6P InChIKeyhelp_outline QEDPUVGSSDPBMD-XTAIVQBESA-N SMILEShelp_outline CCCCCCCCCCCCCCCCCCCCCCCC(=O)N[C@@H](COP([O-])(=O)OCC[N+](C)(C)C)[C@H](O)\C=C\CCCCCCCCCCCCC 2D coordinates Mol file for the small molecule Search links Involved in 1 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H2O Identifier CHEBI:15377 (CAS: 7732-18-5) help_outline Charge 0 Formula H2O InChIKeyhelp_outline XLYOFNOQVPJJNP-UHFFFAOYSA-N SMILEShelp_outline [H]O[H] 2D coordinates Mol file for the small molecule Search links Involved in 6,264 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline N-tetracosanoyl-sphing-4-enine Identifier CHEBI:72965 Charge 0 Formula C42H83NO3 InChIKeyhelp_outline ZJVVOYPTFQEGPH-AUTSUKAISA-N SMILEShelp_outline CCCCCCCCCCCCCCCCCCCCCCCC(=O)N[C@@H](CO)[C@H](O)\C=C\CCCCCCCCCCCCC 2D coordinates Mol file for the small molecule Search links Involved in 3 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline phosphocholine Identifier CHEBI:295975 Charge -1 Formula C5H13NO4P InChIKeyhelp_outline YHHSONZFOIEMCP-UHFFFAOYSA-M SMILEShelp_outline C[N+](C)(C)CCOP([O-])([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 35 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,521 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:45324 | RHEA:45325 | RHEA:45326 | RHEA:45327 | |
|---|---|---|---|---|
| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
| UniProtKB help_outline |
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Related reactions help_outline
More general form(s) of this reaction
Publications
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Role for mammalian neutral sphingomyelinase 2 in confluence-induced growth arrest of MCF7 cells.
Marchesini N., Osta W., Bielawski J., Luberto C., Obeid L.M., Hannun Y.A.
Recently, we reported that neutral sphingomyelinase 2 (nSMase2) functions as a bona fide neutral sphingomyelinase and that overexpression of nSMase2 in MCF7 breast cancer cells caused a decrease in cell growth (Marchesini, N., Luberto, C., and Hannun, Y. A. (2003) J. Biol. Chem. 278, 13775-13783). ... >> More
Recently, we reported that neutral sphingomyelinase 2 (nSMase2) functions as a bona fide neutral sphingomyelinase and that overexpression of nSMase2 in MCF7 breast cancer cells caused a decrease in cell growth (Marchesini, N., Luberto, C., and Hannun, Y. A. (2003) J. Biol. Chem. 278, 13775-13783). In this study, the role of endogenous nSMase2 in regulating growth arrest was investigated. The results show that endogenous nSMase2 mRNA was up-regulated approximately 5-fold when MCF7 cells became growth-arrested at confluence, and total neutral SMase activity was increased by 119 +/-41% with respect to control. Cell cycle analysis showed that up-regulation of endogenous nSMase2 correlated with G(0)/G(1) cell cycle arrest and an increase in total ceramide levels (2.4-fold). Analysis of ceramide species showed that confluence caused selective increases in very long chain ceramide C(24:1) (370 +/- 54%) and C(24:0) (266 +/-81%) during arrest. The role of endogenous nSMase2 in growth regulation and ceramide metabolism was investigated using short interfering RNA (siRNA)-mediated loss-of-function analysis. Down-regulation of nSMase2 with specific siRNA increased the cell population of cells in S phase of the cell cycle by 59 +/-14% and selectively reverted the effects of growth arrest on the increase in levels of very long chain ceramides. Mechanistically, confluence arrest also induced hypophosphorylation of the retinoblastoma protein (6-fold) and induction of p21(WAF1) (3-fold). Down-regulation of nSMase2 with siRNA largely prevented the dephosphorylation of the retinoblastoma protein and the induction of p21(WAF1), providing a link between the action of nSMase2 and key regulators of cell cycle progression. Moreover, studies on nSMase2 localization in MCF7 cells showed that nSMase2 distributed throughout the cells in subconfluent, proliferating cultures. In contrast, nSMase2 became nearly exclusively located at the plasma membrane in confluent, contact-inhibited cells. Hence, we demonstrate for the first time that nSMase2 functions as a growth suppressor in MCF7 cells, linking confluence to the G(0)/G(1) cell cycle check point. << Less
J. Biol. Chem. 279:25101-25111(2004) [PubMed] [EuropePMC]
This publication is cited by 2 other entries.