Modulation of the activity and arachidonic acid selectivity of group X secretory phospholipase A2 by sphingolipids
To investigate the role of sphingomyelin (SM) in the regulation of inflammatory reactions, we studied its effect on the activity and fatty acid specificity of group X secretory phospholipase A2 (sPLA2X). Compared with other phospholipases, recombinant sPLA2X released more arachidonate from HDL. Pret...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2007-03-01
|
| Series: | Journal of Lipid Research |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520432432 |
| _version_ | 1818675688630124544 |
|---|---|
| author | Dev K. Singh Papasani V. Subbaiah |
| author_facet | Dev K. Singh Papasani V. Subbaiah |
| author_sort | Dev K. Singh |
| collection | DOAJ |
| description | To investigate the role of sphingomyelin (SM) in the regulation of inflammatory reactions, we studied its effect on the activity and fatty acid specificity of group X secretory phospholipase A2 (sPLA2X). Compared with other phospholipases, recombinant sPLA2X released more arachidonate from HDL. Pretreatment of HDL with sphingomyelinase (SMase) C activated the sPLA2X activity, but the release of arachidonate was stimulated less than that of linoleate. In liposomes containing synthetic phosphatidylcholines (PCs), sPLA2X showed no clear selectivity among the various sn-2 unsaturated fatty acids. However, when SM was incorporated into liposomes at 30 mol%, the enzyme exhibited strong preference for arachidonate, although its overall activity was inhibited. Degradation of liposomal SM by SMase C resulted in sPLA2X activation and loss of its arachidonate preference. Incorporation of ceramide into HDL or PC liposomes activated the enzyme activity, the release of arachidonate being stimulated more than that of linoleate. SM-deficient cells released more arachidonate than normal cells in response to exogenous sPLA2X. SMase pretreatment of normal cells stimulated the release of arachidonate by the exogenous sPLA2X. These results show that SM not only inhibits sPLA2X activity but also contributes to its selectivity for arachidonate, whereas ceramide stimulates the hydrolysis of arachidonate-containing PCs. |
| first_indexed | 2024-12-17T08:31:34Z |
| format | Article |
| id | doaj.art-ca88c53b31604ccf998ea97277ebabaa |
| institution | Directory Open Access Journal |
| issn | 0022-2275 |
| language | English |
| last_indexed | 2024-12-17T08:31:34Z |
| publishDate | 2007-03-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Lipid Research |
| spelling | doaj.art-ca88c53b31604ccf998ea97277ebabaa2022-12-21T21:56:36ZengElsevierJournal of Lipid Research0022-22752007-03-01483683692Modulation of the activity and arachidonic acid selectivity of group X secretory phospholipase A2 by sphingolipidsDev K. Singh0Papasani V. Subbaiah1Departments of Medicine and Biochemistry & Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60612Departments of Medicine and Biochemistry & Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60612To investigate the role of sphingomyelin (SM) in the regulation of inflammatory reactions, we studied its effect on the activity and fatty acid specificity of group X secretory phospholipase A2 (sPLA2X). Compared with other phospholipases, recombinant sPLA2X released more arachidonate from HDL. Pretreatment of HDL with sphingomyelinase (SMase) C activated the sPLA2X activity, but the release of arachidonate was stimulated less than that of linoleate. In liposomes containing synthetic phosphatidylcholines (PCs), sPLA2X showed no clear selectivity among the various sn-2 unsaturated fatty acids. However, when SM was incorporated into liposomes at 30 mol%, the enzyme exhibited strong preference for arachidonate, although its overall activity was inhibited. Degradation of liposomal SM by SMase C resulted in sPLA2X activation and loss of its arachidonate preference. Incorporation of ceramide into HDL or PC liposomes activated the enzyme activity, the release of arachidonate being stimulated more than that of linoleate. SM-deficient cells released more arachidonate than normal cells in response to exogenous sPLA2X. SMase pretreatment of normal cells stimulated the release of arachidonate by the exogenous sPLA2X. These results show that SM not only inhibits sPLA2X activity but also contributes to its selectivity for arachidonate, whereas ceramide stimulates the hydrolysis of arachidonate-containing PCs.http://www.sciencedirect.com/science/article/pii/S0022227520432432sphingomyelinceramidefatty acid specificityinflammation |
| spellingShingle | Dev K. Singh Papasani V. Subbaiah Modulation of the activity and arachidonic acid selectivity of group X secretory phospholipase A2 by sphingolipids Journal of Lipid Research sphingomyelin ceramide fatty acid specificity inflammation |
| title | Modulation of the activity and arachidonic acid selectivity of group X secretory phospholipase A2 by sphingolipids |
| title_full | Modulation of the activity and arachidonic acid selectivity of group X secretory phospholipase A2 by sphingolipids |
| title_fullStr | Modulation of the activity and arachidonic acid selectivity of group X secretory phospholipase A2 by sphingolipids |
| title_full_unstemmed | Modulation of the activity and arachidonic acid selectivity of group X secretory phospholipase A2 by sphingolipids |
| title_short | Modulation of the activity and arachidonic acid selectivity of group X secretory phospholipase A2 by sphingolipids |
| title_sort | modulation of the activity and arachidonic acid selectivity of group x secretory phospholipase a2 by sphingolipids |
| topic | sphingomyelin ceramide fatty acid specificity inflammation |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520432432 |
| work_keys_str_mv | AT devksingh modulationoftheactivityandarachidonicacidselectivityofgroupxsecretoryphospholipasea2bysphingolipids AT papasanivsubbaiah modulationoftheactivityandarachidonicacidselectivityofgroupxsecretoryphospholipasea2bysphingolipids |